List of glitches (Generation I): Difference between revisions

This article is incomplete. Please feel free to edit this article to add missing information and complete it. Reason: Loads of missing newly discovered glitches; could also use some better organization; probably should make a section for "all handheld games" vs "all games" seeing how there's lots of in-battle glitches that were alternately fixed or still occur in Stadium

This is a list of glitches that occur in the Generation I core series Pokémon games. It applies to both the original Game Boy and the 3DS Virtual Console releases unless otherwise noted.

All games

This section is incomplete. Please feel free to edit this section to add missing information and complete it. Reason: cf. English and other localizations with the original Japanese releases

NOTE: The following glitches affect all Game Boy versions of Pokémon Red and Green (1.0 and 1.1) and of Japanese Pokémon Yellow (1.0 to 1.3) unless noted otherwise.

0 ERROR glitch

Main article: 0 ERROR

A glitch similar to the Mew glitch that causes Route 6 to become glitched.

1/256 miss glitch

In the Generation I handheld games, all moves are 1/256 more likely to miss than was intended, including 100% accuracy moves. In non-Japanese versions, Swift and Bide skip accuracy checks and always hit, regardless of this bug.

Moves with 100% accuracy have a 255/256 (~99.6%) chance of hitting (without accuracy nor evasion modifiers). Other moves also have 1/256 less accuracy than was intended.

The glitch occurs due to the accuracy check using a "strictly less than" comparison instead of a "less than or equal to" comparison. If a randomly generated integer between 0 and 255 (inclusive) is strictly less than the move's accuracy (after applying accuracy and evasion modifiers), the move hits; however, if the random number is exactly 255, the random number cannot be less than the move's modified accuracy (regardless of its value).

In Pokémon Stadium, the randomly generated integer is between 0 and 254 (inclusive). This prevents moves with 100% accuracy from missing, but also slightly increases the probability of lower accuracy moves of hitting.

In Pokémon Gold and Silver, if the move has 100% accuracy (after applying accuracy and evasion modifiers and the BrightPowder modifier), the move skips the rest of the accuracy check and hits. This prevents moves with 100% accuracy from missing, but does not affect the chance of hitting for moves with lower accuracy.

Battle draw theme oversight

Prior to Generation II, having the player character draw in a Pokémon battle causes the victory theme to play even though the player has lost.

Disabling NPCs animation

When the player walks, the screen moves the objects of the stage where player is, including NPCs. That movement alters the animations of the NPCs, disabling their animations.

Bide errors

The stored damage from Bide can hit (but not always) a Pokémon under the invulnerable stage of Fly or Dig. If Bide deals damage to a Pokémon under Fly or Dig, the game will reveal its sprite early. This also causes a small animation glitch with Dig where it appears that the enemy Pokémon rises from the ground off the top of the screen instead of the enemy rising up from 'underground'. There is no animation glitch with Fly because the game has no animation on the opponent's side of Fly returning from the top of the screen to the ground—the game only reveals the sprite.

Cable Club escape

Main article: Cable Club escape glitch

Catch rate RNG oversight

Due to the combination of the way the games' random number generator is implemented and the capture algorithm using rejection sampling to generate a random number from a limited range for Great and Ultra/Safari Balls, there is a significant bias to RNG outcomes for these balls; Ultra Balls can for instance be less effective than Poké Balls against Pokémon with high catch rates at full health, and Pokémon with lower catch rates are significantly harder to catch in an Ultra or Safari Ball at full health than they should, while being easier to catch at low health.^[1]

Changing NPC sprites

When the walking through walls glitch is used and the player flies to Lavender Town, they can activate this glitch. They must walk down to Route 12 and walk through the side of the gate rather than actually going into the gate. Once this has been done, every NPC will have the same sprite as the player. Encountering a wild Pokémon fixes the sprites. This is due to the fact that the game fails to load the sprite graphics properly.

Counter glitches

Counter may strike back damage from an attack that isn't Normal- or Fighting-type. For this to happen, the Counter target must have not selected any move the turn Counter was used (for example, due to being frozen, asleep, or switching out), and must have moved first and used a Normal- or Fighting-type damaging move the previous turn. In addition, Counter may also strike back damage from one's own attack. This occurs if the Counter target previously used a Normal- or Fighting-type damaging move before the Counter user successfully used any damaging move during the same turn. If, in the next turn when Counter is used, the Counter target doesn't select a move, the Counter user's own damage will be dealt.

In Link Battles, Counter may also trigger desynchronization errors. This occurs due to the last move pointed by the cursor in the move selection menu being treated by the last move actually used if the Pokémon switches out. This oversight can also be exploited outside of link battles to make the opponent's Counter hit or miss at will under specific circumstances.

Critical hit ratio error

Focus Energy and Dire Hits are intended to quadruple the critical hit rate, but due to a glitch, they will quarter the chance of scoring a critical hit. This was fixed in Pokémon Stadium.

Cut glitch

The Cut glitch can refer to two different glitches in Generation I involving the move Cut.

Invisible tree

There is a tree near the bottom of Route 14. If this particular tree is cut down and then the player walks five steps west from where the tree was (so that the spot where the tree used to be is at the edge of the screen) and then walks back their path will be blocked as if a tree was still there. Even though the tree is not visible, it can still be cut down normally using the move Cut.

Standing on a tree

Red standing on top of the tree outside Vermilion Gym

Pikachu standing on top of a tree in Celadon Gym

If the player cuts down a tree, stands on the spot where the object was, saves, turns the game off, then loads it, the player will be standing on the tree. The same can happen with Pikachu in Pokémon Yellow.

In Celadon Gym in Pokémon Yellow, Pikachu can also end up standing on a tree after certain battles.

This glitch occurs because the Generation I engine would not store the data needed to remember that the tree had been cleared.

Cycling Road access requirement bypassing

If the player does not have a Bicycle (or it has been deposited in the PC), it is still possible to reach Cycling Road by holding down the left button while the guard attempts to prevent the player from entering the Cycling Road. Upon entering Cycling Road, the player will be automatically riding a bike, despite not having one.

This is because pressing left on the d-pad actually overrides the "walk back to the right" movement, thus ignoring the return movement.

Defrost move forcing

If a frozen Pokémon is defrosted before it would have moved that turn, it uses a move that turn, even though it couldn't select a move that turn due to being frozen. However, this move can differ between the games in a link battle, causing desynchronization. Additionally, this can also allow a Pokémon to use a move with no PP remaining, causing an underflow.

If a Pokémon is defrosted, in the game of the owner of the defrosted Pokémon, the move used will be the last move the player had the cursor over. Since the player does not get to select a move while frozen, this can be a move of another Pokémon in the party. The value that manages this is set to 0 at the start of a link battle, so if the player has never moved the cursor over a move during that battle, the used move will be the glitch move --.

In the game of the other player, the move used will be the last move used by the defrosted Pokémon (reset upon switching), or the first listed move if it has not used a move since switching.

PP is deducted from the move the Pokémon uses in other player's game (even in its owner's game), regardless of its current PP. If the move had 0 PP, it underflows to 63 PP and removes the effect of one PP Up.

Division by 0

During damage calculation, the game will eventually attempt to divide by 0 in the following two cases. In both cases, this causes the game to freeze indefinitely (due to the algorithm looping infinitely).

The attacker's current Attack/Special stat is higher than 255 and the defender's current Defense/Special stat is lower than 4.

The defender's current Defense/Special stat is 512 or 513 and the defender has used Reflect/Light Screen. In addition, if its current Defense/Special stat is 514 or higher when Reflect/Light Screen is up, it will be treated as if it was much lower due to a roll-over glitch.

Dual-type damage misinformation

In Generation I, Pokémon with two types that have a weakness and resistance to the same type receive neutral damage from that type, but the incorrect message is displayed.

For example, Grass-type moves do neutral damage to Gyarados, but if Gyarados is hit by a Grass-type move, the game erroneously states that the attack is "not very effective...".

The game prioritizes on which message to display for each 'special' scenario (where normal damage is not dealt) based on each scenario's internal ordering. The higher the ordering determines what message the game will display. Grass against Water as 200% damage for instance is the 4th entry, whilst Grass against Flying as 50% damage is the 27th. Consequently, in this example, the game chooses the message for scenario #27, returning the wrong message "It's not very effective...".

This glitch does not occur in Pokémon Stadium.

If an attack is super effective or not very effective against one type and does no damage against another type (for example, Dig against Charizard), the game will erroneously state that the attack missed.

Order of priority of messages

This list is presented in the reverse order to which they are stored in the game data. Messages higher on the list take priority over those lower on the list.

Exp. All oversight

Main article: Experience#Apparent Exp. All programming error in Generation I

If the player has an Exp. All in their bag and uses two or more Pokémon from their party in battle, then the total amount of experience gained overall will be decreased depending on the number of Pokémon used.

Experience PC withdrawing glitch

In Generation I, attempting to withdraw a level 1 Pokémon using the "Medium Slow" growth algorithm will softlock the game. This also applies to Pokémon using the "Medium Fast" growth algorithm for Level 255, "Fast" for Level 255, and "Slow" for Level 237.

Certain glitch Pokémon use invalid growth algorithms and have the game freeze when they are withdrawn at specific levels as well. For example, in Pokémon Red and Blue, 'M (00) uses an invalid experience curve 26 and the game will freeze if the player attempts to withdraw a level 0 'M (00). Level 0 'M can be found with the old man glitch if the player does not pick a preset name.

Additionally, if a Pokémon in the "Medium-Slow" growth algorithm is withdrawn between Levels 245 to 255, it will become a Pokémon with a level between 59 and 125, depending on the exact Level of the Pokémon deposited. A Pokémon in the "Medium-Slow" growth algorithm that is withdrawn between 238 and 255 will become a Pokémon with a level between 39 and 146. A Pokémon withdrawn in this manner will have its stats recalculated, which may lead to it having more HP than its maximum HP.^[2][3]

Experience underflow

Main article: Experience#Experience underflow glitch

In Generations I and II, level 1 Pokémon using the "Medium Slow" growth algorithm will jump from level 1 to level 100 after gaining a low amount of experience points.

Ghost Bicycle glitch

In Generation I games, if the player saves at the Cycling Road and then creates a new game, it will not be possible to use the Bicycle or Surf anywhere until this glitch is fixed. If the player attempts to use either of them, it will fail and the game will display the same error message that would appear if the player tried to do this in the Cycling Road itself.

Even with this glitch active, the player can still surf by using the surfboard item named "?????", which is not legitimately obtainable.

This glitch exists because the bit 5 of the memory address D732 (D731 in Yellow) is turned on while the player is in the Cycling Road, which causes the player to be unable to use the Bicycle or Surf. When the player creates a new game, usually all the data from a previous game would be deleted, but this memory address remains in the new game.

This glitch is fixed (that is, the memory address is properly updated) if the player blacks out (either in battle or the overworld), uses Dig, Teleport, or Fly outside of battle, uses an Escape Rope, or enters and leaves the Cycling Road.

See also: WRAM clear oversight (Generation I) in Glitch City Laboratories.

Ghost identity unveiling

When encountering a ghost in Pokémon Tower without having a Silph Scope, it is possible to see its true identity by viewing the stats of any Pokémon in the player's party. However, this glitch is only graphical, and it is still impossible to fight or catch it.

Ghost Marowak bypassing

Using a Poké Doll on the ghost Marowak in Pokémon Tower with or without the Silph Scope will cause it to permanently disappear.

Glitch City

Main article: Glitch City

Hall of Fame corruption

Some corrupted Hall of Fame entries

Main article: MissingNo.#Glitches caused

When glitch Pokémon have been seen on the save file, the player's Hall of Fame is badly corrupted with entirely different Pokémon, even glitch Pokémon, and very glitched characters, names and levels. This does not affect the Pokémon themselves, rather the data seen in the Hall of Fame, and is caused by the contents of the sprite decompression buffer that is stored in SRAM overflowing into memory allocated for save data when a glitch Pokémon's sprite is decompressed.

Haze opponent crippling

If Haze is used to thaw a frozen Pokémon when it still needs to recharge from Hyper Beam, the Pokémon will thaw out but it will be unable to make a move until it faints even if a Fire type move is used later. This glitch was fixed in Pokémon Stadium.

It is similar to the Sky Drop glitch in Generation V, because both glitches permanently make the opponent unable to move until it faints or is switched out (although switching out the Pokémon is normally not possible).

HP recovery move failure

If a Pokémon uses a recovery move (Softboiled, Rest or Recover) and the difference between its current HP and maximum HP is 255 or 511 (or any number that leaves a remainder of 255 when divided by 256), the move will fail the same way it would when the difference is 0. This glitch does not occur in Pokémon Stadium.

This is caused by the comparison that checks whether the current HP matches the maximum HP erroneously not correctly incorporating the upper byte of the HP values.

Hyper Beam + Sleep move glitch

If a Pokémon that has just used Hyper Beam and has yet to recharge is targeted with a sleep-inducing move, any other status it may already have (paralysis, burn, poison, or freeze) will be ignored and sleep will be induced regardless. In addition, the sleep-inducing move will never miss, as it will skip any accuracy checks in a similar way to Swift.

Furthermore, if the Pokémon was badly poisoned (by Toxic), the Toxic counter will not be reset.

Index #000 post-capture

In Generation I, if the player manages to capture an 'M (00) or 3TrainerPoké $ an invisible wild Ditto will still be in battle with the player where 'M (00) was before, and the battle will not end. This Ditto can then be caught.

Invisible Prof. Oak

If the player attempts to leave too many times when choosing their first Pokémon then the player, Prof. Oak and the middle Poké Ball's sprites will vanish. Pressing start will pull up some glitched text on the screen, but exiting the start menu will fix everything.

Invulnerability glitch

In Generation I, if a Pokémon is fully paralysed or hurts itself in confusion while in the semi-invulnerable stage of Fly or Dig, all moves (with the exception of Swift, Transform and possibly the unleashed damage from Bide) from the opponent will miss or fail until the user switches Pokémon, finishes the battle or successfully performs a charging move (specifically, Fly, Dig, Razor Wind, Skull Bash, and Solar Beam). The user's Pokémon can attack normally during this glitch.

This glitch was fixed in Pokémon Stadium.

Item duplication glitch

Main article: Item duplication glitch

Item underflow glitch

Main article: Item underflow

Landing on an NPC

If the player lures an NPC below a ledge that can be jumped over (by blocking their movement in certain directions), it is possible to land on top of the NPC when they jump over the ledge.

Level-up learnset skipping

Pokémon cannot learn moves they should learn at a level if they earn enough experience at once to skip that level.

For example, if a level 4 Pidgey earned enough experience points for defeating a single Pokémon to reach level 6, it will not learn Sand-Attack, a move it would normally learn at level 5.

Leveling past 100

In Generation I and II, if a Pokémon is obtained at a level above 100, it can be leveled up with Rare Candies up to level 255. If a Rare Candy is fed to a level 255 Pokémon, its level will be reset to 0 due to an overflow in a single byte. If a Pokémon above level 100 levels up due to experience, its level will be reset to 100.

Menu glitch

If the player holds A when the game is saving, the menu won't disappear until player stops holding A.

Mew glitch

Main article: Mew glitch

Mirror Move glitch

During a Link Battle, if Mirror Move and a binding move (such as Wrap or Fire Spin) are used together, the two player's games may become desynchronized due to one game interpreting that the attack used was Mirror Move (and failing) and the other game interpreting that the binding move was used instead.

Pallet Town NPC misplacement

If the player stands outside of Professor Oak's Lab in Pallet Town, the person outside it will eventually stand on the Lab's door. This is because the door tile was programmed as a non-solid tile.

Perpetual spinning animation

If the player saves the game having just entered the Safari Zone and leaves, the game assumes that the player is just entering the Safari Zone entrance, as it does not save that the player is currently in a paid Safari Zone session. Thus, upon passing by the desk, the player is prompted to pay for another Safari Zone session, although they are now traveling out towards the town below. Because the player is supposedly in a Safari Zone session, the game counts down steps passively. Upon exiting towards the bottom into Fuchsia City, the player must Fly to Viridian City and enter Giovanni's Gym. Inside, the player must walk along the spinners, proceeding to be spun around. After taking enough steps to deplete the (invisible) counter, the player freezes, the PA "ding-dong" noise will sound, and a message will pop up saying that the player's Safari Zone session is now over. If the player is in the middle of a spin while this happens, the player will be transported to the Safari Zone entrance as if they had just left the Safari Zone, and upon moving will perform the spin animation, and move slower. The player has full control over the movement of the character; the only difference is that instead of the walking animation, the spinning animation is played.

The glitch can be fixed by returning to the location where the player ran out of Safari Zone steps.

Changing the Player's sprite

A sub glitch involves changing Red's sprite into the sprite of another NPC. While the player is in the perpetual spinning state, they must enter a Pokémon Center then turn on the PC while hold left, then close the PC while still holding left. Red's sprite will now be replaced with the overworld sprite of an NPC based on the location of the Pokémon Center. The following list shows the towns that correspond to which overworld sprite the player will be turned into:

• Pallet Town: Professor Oak
• Viridian City: Professor Oak
• Pewter City: Lass
• Cerulean City: Lass
• Vermilion City: Lass
• Lavender Town: Jr. Trainer ♂
• Celadon City: Police officer
• Fuchsia City: Swimmer
• Saffron City: Jr. Trainer ♂
• Cinnabar Island: Professor Oak
• Indigo Plateau: Police officer
• Routes: Lass

Leaving the building or not moving will return Red's sprite back to normal.

Poison/Burn animation with 0 HP

If a poisoned/burned Pokémon with low HP is confused and in the next turn loses its HP, the HP will be 0, but before it faints, the message and the animation of the poison/burn will appear, although the Pokémon doesn't have any HP. This also happen with a move which reduces the user's HP, like Take Down. This was fixed in Pokémon Gold/Silver.

Pokémon merging

Main article: Pokémon merge glitch

Pokémon Storage System cloning

Main article: Cloning glitches#Storage system method

Pokémon Storage System healthy party deposit

It is possible for the player to deposit all Pokémon except fainted ones and a black out will occur but only after four steps in the same session. In Red and Blue it is possible to progress further by saving the game before traveling four steps to reset the 'remaining step count' to 4 when the game is reset, though this is no longer the case in Pokémon Yellow because the remaining step count was changed to default to 1 step. The player immediately has a black out if entering a battle with just fainted Pokémon.

Prevented progress

If the player has at least two Pokémon registered as caught in the Pokédex before obtaining it from Oak (either multiple non-related species or an evolved form of the starter Pokémon), the game will assume that they already have the Pokédex, and will not allow them to proceed.

This glitch affects all versions of the Japanese Red, Green (1.0 and 1.1), Blue, and Yellow (1.0 to 1.3). The glitch is fixed in the international releases of Pokémon Red and Blue, but remained in the international releases of Pokémon Yellow.

In the Japanese Pokémon Yellow, it is also possible to perform this glitch by exploiting the save corruption glitch.

Psywave desynchronization

If a Pokémon uses Psywave in a link battle, there is a small chance the games will generate a different number of pseudo-random numbers, causing desynchronization.

When a Pokémon uses Psywave, a random number is generated between 0 and 255. If the player uses Psywave, if the generated number is greater than or equal to 1.5× the Pokémon's level (rounded down) or it is 0, the number is discarded and a new number generated; if the opponent uses Psywave, if the generated number is greater than or equal to the Pokémon's level, the number is discarded and a new number generated. As such, if the generated number is 0, the Psywave user's game will generate a new number, whereas the non-Psywave user's game will not. This causes all subsequent pseudo-random numbers to be desynchronized.

Psywave infinite loop

If a level 0, 1 or 171 Pokémon uses Psywave, the game will continuously generate pseudo-random numbers, hanging indefinitely. However, this is not an issue in normal gameplay, as Pokémon can only be obtained at these levels via glitches.

When a Pokémon uses Psywave, a random number is generated between 0 and 255. If the generated number is greater than or equal to 1.5× the Pokémon's level (rounded down) or it is 0, the number is discarded and a new number generated. As such, there is no number that can be generated for a level 0 or level 1 Pokémon that will not result in the result being discarded and a new number being generated.

If a level 171 Pokémon uses Psywave, the upper bound would be 256; however, since this value is stored in a single byte, it overflows to 0, causing the same issue as a level 0 Pokémon.

Red Bar Glitch

If a Pokémon is in a critical health status, the game will start to play a sound to let the player know their Pokémon is low on health and about to possibly faint. This sound has an unintended side effect of causing other sounds and animations to not play. This glitch has become very well known and is used often in speedruns for the Generation I games.

Rematching Trainers

To perform this glitch, the player must have some Pokémon which can lose a battle easily, so they may wish to have one Pokémon, a poisoned Pokémon or both. They must be inside a cave, e.g. Mt. Moon or Victory Road. They must, finally, have access to an unbattled Trainer who is in a cave. They must encounter a wild Pokémon while in a Trainer's eyeline. This wild Pokémon must proceed to defeat the player, sending them to a Pokémon Center. They then must re-enter the cave the Trainer is in. The Start menu will pop up. Upon closing it, the Trainer they escaped from will fight the player. However, if the player defeats them, this is not interpreted as beating the Trainer, and the player can challenge them again.

Rhydon glitch

Main article: Rhydon glitch

Save corruption

In Red, Blue, and Yellow, with no save file, when the player saves the game and turns off the power a little time after the Yes/No box disappears the player will have 255 Pokémon in the party the next time the file is loaded.

If the player turns the power off at the wrong time, the save file will either be corrupted or will appear normal. The right time to pull off the glitch is about twenty frames after the A button is pressed, but in Yellow it is about ten frames later.

The first few Pokémon are level 255 'M (FF) (Red/Blue) or Q_◣ (Yellow), with all of their stats as "F35" (65535), four TM55 as their moves with 63/0 PP and with a nickname and OT of many repeating "9"s. Pokémon past number six do not have all of these properties.

The data regarding Pokémon past the sixth position use other parts of the game's memory misinterpreted as Pokémon data, therefore swapping these Pokémon around or healing them can affect the game. If the player switches the first Pokémon with the tenth Pokémon, they will have 255 items. Switching the items past slot 20 will allow for more precise memory editing because there are only two pairs of memory addresses manipulated; displayed as an item and item quantity, while a "post-six" Pokémon uses many more bytes.

After performing the glitch, the poison effect will occur as the player walks around. In English versions, swapping the first-ninth Pokémon with the tenth will cause to player to have seen and owned 152 Pokémon in the Pokédex.

The Pokémon in the 10th slot will change to a different glitch pokemon as the player walks around to different areas, making it theroetically possible to obtain every Glitch Pokémon in the game.

Using the following equation, it is possible to calculate what memory address any item, including invalid items is using, provided that the memory address is odd.

Memory address = [First item position address -1] + [Cursor position] + ([Cursor position -1])^[4]

The item address that follows an item is displayed as a quantity.

Beating the game quickly

As there are no memory protection measures in place in the Generation I and Generation II games, it is possible to use this glitch to do a number of things, such as beating the game in under five minutes. Below is one method of doing this that requires no luck manipulation:

In Pokémon Yellow, the memory address D364 is used for the last map location for walking through certain exits, including the exit for Red's house and the first item position address is D31D. This means that the correct cursor position can be expressed as:

D364 = D31C + [cursor position] + [cursor position -1]

This has no actual answer because D364 (54116) is even, so the address must be a quantity, but if D363 is used, the answer comes to hex: 24 (dec: 36). Therefore, the memory address D363 (current block of the player's X-position) corresponds to item position 36 (hex: 24) and the quantity of item 36 is the aforementioned warp location address. The cursor position in hexadecimal can be checked by highlighting an item in game and checking the memory address CC35.

As the index number of Pallet Town is 0, the player can access 255 locations by tossing the 36th item (as tossing one ×0 item causes an underflow to 255). The index number of the Hall of Fame room is 118, so the player must toss exactly 138 of item 36 to change the warp destination to the Hall of Fame. If the player stands on the right side of the exit mat item 36 should be a Master Ball, while if the player stands on the left side of the exit mat, it should be the hex:00 glitch item which would appear as some glitchy blocks with a multiplication sign in it.

In Japanese versions

The glitch works in Japanese Blue but the game has to be reset some time after the "!" mark appears in "(PLAYERNAME)はレポートに しっかり かきのこした!". In Japanese Yellow it is possible with the same procedure as English Red/Blue and Yellow, but in order to corrupt the number of items the player has to replace the ninth Pokémon instead of the tenth to avoid a freeze after closing the items pack.

Save data carryover

Using a procedure similar to the save corruption glitch, it's possible to begin a new save file, but having the party Pokémon from the previous save file. With an already existing save file, player must start a new game then save to overwrite the previous save, but turn off the game or reset shortly after the Yes/No box disappears. The exact timing is a difficult two frame window, doing it too early corrupts the previous save file and doing it too late completely overwrites the previous save file.

If successful, the player will begin the new save data while having the party Pokémon from the previous save file in their party. This glitch can be used at the beginning of the game to obtain all three starter Pokémon without trading.

Save reset oversight

This is a glitch that causes the player to always receive the "You can't get off here." message when trying to use the Bicycle even when they are not on the Bicycle. It also causes the "Cycling is fun! Forget Surfing!" message to appear when trying to use Surf (using the ????? "Surfboard" item doesn't cause this message to appear).

If the player's current save is on Route 16, Route 17 or Route 18 (Cycling Road), the WRAM address D732 (D731 in Pokémon Yellow) is normally set to 21h (5th bit is on).

Normally when the player brings up the Continue/New Game/Option menu many of the variables from the current save are loaded so that the game works properly when the player selects the "Continue" option. Most of these variables are reset back to their default value if a new game is loaded but not the WRAM address D732 (possibly due to an oversight by the game developers).

This means starting a New Game with the current save on Cycling Road will cause the "You can't get off here." message to appear when trying to use the Bicycle from any location. The effects of this glitch are only visible once the player obtains the Bicycle or the Soul Badge and a Pokémon with Surf.

The glitch can be fixed by performing any one of these actions:

• Using Dig, Teleport, Fly, or an Escape Rope
• Entering and leaving Cycling Road
• Blacking out (both in battle and in the overworld)

It has been reported that this glitch may occur without starting a new save file when the current save is on Cycling Road, but the cause is unknown.^[5]

Another version of this glitch can (but not always) appear when performing the Fossil conversion glitch in the Japanese Red, Green, and Blue.^[6] Unlike the "New Game" version, entering and leaving Cycling Road doesn't fix the glitch.

Save Surf exploit

The glitch is performed by standing next to a water tile that is facing up, left, or right, walk in that direction and pressing start without letting go of the D-Pad. The game then needs to be saved and reset. When loading the saved data, the player will be facing in the direction that was being held down when the start button was pressed. Using Surf will cause the player to surf on the tile immediately south, even if it is not a water tile.

When loading a save file, the player usually starts facing south. This is because of the limited data in the game. This glitch causes the player to face in a different direction, which confuses the game.

Since statues are treated as water tiles, this glitch can be performed by using a statue as the water tile. Most notably, this glitch can be used to bypass the sailor in order to re-board the S.S. Anne after it has set sail.

Silent Indigo Plateau

In the battle against Blue at Indigo Plateau, if the player evolves a Pokémon in battle and defeats Blue, the music will be muted until Professor Oak comes to congratulate the player.

Sprite corruption

The sprite corruption as seen in Generation I games

The sprite corruption glitch is a glitch that alters the appearance of the sprites in Generation I, making the sprites appear to be cut into pieces or even unrecognizable in some instances.

In Generation I, many glitch Pokémon will distort battle sprites upon their encounter; however, this can be fixed by viewing the stats of a non-glitched Pokémon in the overworld. There are other methods to the glitch, some of which involve using a Pokémon Center to heal the player's Pokémon when in a glitched area, visiting Glitch City, or catching certain glitch Pokémon.

In other generations, it may occur when a cheating device is used.

Stat modification errors

Every time a Pokémon successfully uses a move that affects a stat stage (either raising for example with Double Team, or lowering it for example with Screech) of any of the two Pokémon in battle, the following happens:

• The stat in question is recalculated from its out-of-battle stat and stat stage.
• If the target was the player's Pokémon, badge boosts are applied to all of its stats (if the player has the corresponding badge), boosting them by 1/8.
• If the Pokémon whose turn it is not is paralyzed, its current Speed stat gets quartered.
• If the Pokémon whose turn it is not is burned, its current Attack stat gets halved.

This leads to three notable unintended stat-related effects:

• Whenever one of the player's Pokémon's stat stages is modified, all of its other badge-boosted stats are multiplied by 1.125 again, even though they were already boosted. (The affected stat is recalculated correctly.) This effect can stack until a stat reaches the maximum of 999.
• When a Pokémon is burned or paralyzed, the Attack/Speed drop from the status will be applied again whenever its opponent uses a move that modifies stat stages (either raising its own or lowering the enemy's). This will similarly stack until the stat in question has dropped to the minimum of 1.
• When a burned or paralyzed Pokémon raises its Attack or Speed stat respectively with moves such as Swords Dance or Agility, the stat is recalculated in accordance with the boosted stat stage, but the status drop is not applied to it afterwards (since it's erroneously applied to the wrong Pokémon), effectively nullifying its effects.

All of these issues were fixed in the Pokémon Stadium series.

Statue water tile oversight

The player can use Surf or a Fishing rod when facing the right or left of a Gym statue. The Old Rod continues to pull up Magikarp, as it ignores location, but the Super Rod (and the Good Rod in Yellow) will display the message "Looks like there's nothing in here..." everywhere other than the Cerulean Gym, which has wild Pokémon normally.

Struggle bypassing

In Generation I, a Pokémon can avoid using Struggle by allowing the game to self-select a move to be used, which can happen to any move used immediately after a Pokémon is thawed out after being frozen, or due to the effects of one of several moves (Bind, Clamp, Fire Spin, Hyper Beam, Metronome, Mimic, and Wrap) because of the auto-selection involved with binding moves. A move used with 0 PP in this way underflows to the maximum possible value, 63 PP; due to the way the data is structured, if this occurs, a move on which 0 PP Ups had been used will gain full PP Up status, while a move on which PP Ups had been used loses one PP Up boost.

From Generation II onward, this bug is addressed by preventing a move from being executed if it has 0 PP.

Substitute HP drain bug

In Pokémon Gold, Silver, and Crystal, the Japanese versions of Pokémon Red, Green, Blue, and Yellow, and the Pokémon Stadium series, HP-draining moves always miss when used against a target that is behind a substitute.

In the Western versions of Pokémon Red, Blue, and Yellow, HP-draining moves are supposed to behave the same way, but instead can hit the substitute (like any other move) due to a programming oversight.

Substitute sprite vanishing

Using a sacrificial move like Explosion on a substitute and having the damage break the substitute prevents the user from fainting. The sprite of the user vanishes regardless.

Substitute + Confusion glitch

If a Pokémon with a Substitute up hurts itself due to confusion, or due to Jump Kick's or Hi Jump Kick's side effect, damage will be dealt to the opponent's Substitute instead. If the opponent doesn't have a Substitute up no damage will be dealt to any Pokémon.

Substitute and Minimize glitch

If the enemy uses Substitute or Minimize and the player goes to view the stats of any Pokémon and then return to the battle, the sprites will be changed. The enemy will have the sprite of the Pokémon's player but broken, and the Pokémon of the player will have the Substitute or Minimize sprite. The sprite of the rival can change if the player goes to view the stats of any Pokémon in the team.

Super Glitch

Main article: Super Glitch

S.S. Anne reboarding

The player surfing on top of the sailor

After the S.S. Anne leaves the dock for the first time, it's possible to make it reappear later. To perform this glitch, the player must stand one tile above and to the left of the sailor guarding the harbor, take a step right and hit the Start button at the same time, save and reboot. After verifying that the player is facing right and without moving, a Pokémon must be selected to Surf, thus making the player surf on top of the sailor. Then, after walking down to the harbor, the boat can be entered.

Toxic counter glitches

With Leech Seed

If the target of Leech Seed is also under the effect of Toxic (or was under that effect and healed itself with Rest), because Leech Seed and Toxic both use the same damage algorithm, Leech Seed damage will be affected by Toxic's N parameter, and will increase each turn. This does not occur in Generation II onward.

With Rest

If a Pokémon badly poisoned by Toxic uses Rest, the Toxic counter will remain, with the N value not being reset. If a Pokémon is then poisoned, burned, or affected by Leech Seed, the damage will draw upon (and increment) the N value, and will increase each turn. This does not occur in Pokémon Stadium or Generation II onward.

Trade cloning

Main article: Cloning glitches#Trading method

Transform glitches

Main article: Transform glitches

Trapping sleep glitch

To perform this glitch, player's Pokémon has to be bound by another Pokémon. Because it is bound, the player should use healing items until the binding ends. If the opposing Pokémon then puts player's Pokémon to sleep on the turn the binding ends, the player's Pokémon will never move. To fix the glitch, the player has to cure the sleep status.

Vending machine glitch

If the player has enough money to buy a Fresh Water (at least $200) but not enough to afford a Soda Pop or Lemonade, the vending machines atop Celadon Department Store still allow these more expensive drinks to be purchased. The player's money will be reduced to $0 rather than becoming a negative number.

Victory Road Bicycle music quirk

If, while riding the Bicycle in Victory Road, the player falls through a hole, they will, on landing, no longer be riding the Bicycle; nonetheless, the Bicycle theme music will continue to play until the player enters a battle, leaves the dungeon, changes floors, or resets the game.

This glitch occurs neither in the Japanese nor the international versions of Pokémon Yellow; instead, the Bicycle music does not play at all in Victory Road.

Walking through an NPC

If the player lures an NPC onto the path that Professor Oak takes to bring the player to the laboratory, Professor Oak and the player will walk right over and through her.

Walking through walls

To walk through walls, the player must first trick the game into letting them exit the Safari Zone while it still thinks the Safari Game is running. To do this the player must enter the Safari Zone, paying $500 to play. Next the player must try to exit the Safari Zone, but when asked if they want to leave early, they must select no. Now, the player must save the game and restart. When the game loads, the player must again exit the Safari Zone, but this time, the attendant will treat the player as if they entered from Fuchsia City, and when the attendant asks if the player wants to play the Safari Game, the player must select no. From there on there are two methods to doing the glitch

Ledge jump method

For this method, the player must first get a poisoned Pokémon before entering the Safari Zone, and deposit all of their other Pokémon in the PC. Either the poisoned Pokémon must have high HP (over 124) or the player must have enough Potions to keep it from fainting too early. Then the player must enter the Safari Zone only with the poisoned Pokémon, then follow the above steps.

After setting up the glitch, the player then jump off a ledge exactly when the game thinks the Safari Game should end. When the player jumps off a ledge, they temporarily lose collision interactions with solid objects until they land on the lower ground, so if the game transitions to another map before the player can land, the collision interactions are never restored. To make extended use of this glitch, the player must also black out while inside the Safari Zone's entrance building after being warped back when the Safari Game ended.

From there, the player must walk 499 steps, ending at a position in the city where they can jump off a ledge with one more step. (The poisoned Pokémon loses HP every four steps and causes the screen to flash, so it is possible to count 124 flashes and take 3 further steps. By the same token, it is also possible to calculate a loss of 124 HP for the poisoned Pokémon and track its HP.) If the poisoned Pokémon has less than 124 HP, a Potion must be used on it to prevent it from fainting.

After the player has walked 499 steps and is in an appropriate position, they must jump off the ledge so that they are in midair when they run out of steps for the Safari Game (with the glitched drop shadow sprite underneath the player). They will be warped back to the Safari Zone entrance building and the background music will stop. The player is now able to walk through walls, but attempting to leave the building without the doors at this point would cause the game to crash. Talking to the man will only cause him to say "Welcome to the Safari Zone" without actually asking if the player wants to enter. If the player enters the Safari Zone, they will have over 100 Safari Balls and possibly infinite steps, but the player can't walk through walls anymore. If the player walks around in the building until the poisoned Pokémon faints, they will black out and be warped to the last Pokémon Center they healed at, and from there they will be able to walk through walls anywhere outdoors. The glitch wears off when entering a door (the normal entrance square to the bridge to the S.S. Anne where the NPC normally stops the player counts as a door).

Pewter Museum guide NPC method

Another simpler method is to use the NPC that guides the player to the Pewter Museum of Science. What the player must do is run out of Safari Zone steps during the cutscene where the NPC is guiding the player to the museum. If done correctly, the player will be teleported to the Safari Zone entrance, then upon leaving will instead be exiting from the PokéMart in Pewter City and a textbox pops up. Then they must save and reset.

Afterwards the player will find the NPC infinitely walking downwards and looping each time he goes offscreen. The player must then talk to him while standing to the right of the Pokémon Center entrance, which begins a walking sequence with the menu repeatedly popping up. Holding B allows the player to walk anywhere except down. If player uses Fly, they will be able to walk through walls in any direction while holding the B button, until they enter a door or Trainer battle.

Outcome

If done correctly the player will enter a state where they can walk through any solid object. If the ledge jump method was used, the player can still talk to NPCs and interact with them as normal. If the Pewter Museum guide method was used, the player cannot interact with NPCs or objects on the overworld. Trainer battles will still trigger (however, upon completion of the battle, normal collision effects will be restored) and normal chat dialogue will remain. The player can interact with the "on display" Pokémon in Fuchsia City where their only dialogue is "!". If the player heads to Cycling Road and finishes a trainer battle, they can walk around without a bike. If the player battles a trainer while standing on water, they will be unable to move in any direction without the use of Surf after the battle.

The player is also able to fly and retain the ability to walk through walls. Under certain scenarios, this glitch may trigger the Glitch City glitch. Depending on the location, the overworld can have incorrect tilesets. For example Indigo Plateau has a unique tilesets, thus Flying there then walking in other places in Kanto causes buildings and other tiles to look unusual.

Saving the game and reloading it restores normal collision effects. If the player stands on Cycling Road and saves and loads the game, they can walk around on Cycling Road without a bicycle. Saving and loading the game while on a water tile causes the player to be unable to move without the use of Surf. Saving and loading the game while standing on top of the guard to the S.S. Anne allows the player to enter the bridge and then the ship. If an NPC forces the player to move, the glitch is cancelled.

This glitch may also replace the sprites of some Trainers.

Yami shop

The "Yami shop" glitch changes the selection of items that can be bought in any Poké Mart. To perform it the player must have obtained a glitch item with an unterminated name, one recommended item is "PC" in Pokémon Red and Blue which can be obtained with item underflow. The player must first open the Pokémon menu in a certain location, the most recommended location is in front of the cashier, however it can be done in certain other locations as long as at least one tree tile is between the Pokémon menu and player's name, and the player does not open the Start menu again before speaking to the cashier. Next the player should attempt to sell the glitch item and cancel (sometimes the player is unable to sell it). The music will then fade out, then at this point the player should select "Buy".

Doing this corrupts the selection of purchasable items, allowing glitch items or normally non-purchasable items to be bought. The player can now buy items such as Safari Balls or Master Balls, and other items which normally cannot be bought (Oak's Parcel, Gym Badges, etc). Many items that are normally unable to be bought will not have a price. The selection of items vary depending on where the player last opened the Pokémon menu.

ZZAZZ

Main article: ZZAZZ glitch

Red and Blue

All releases

Evolution stone bypassing

	This glitch is in need of research. Reason: Glitch Pokémon which evolve by items You can discuss this on the talk page.

Pokémon that evolve by Evolution stone can be evolved without the use of an Evolution stone after a battle. If the Pokémon has leveled up during the battle, and the battle has been finished with another Pokémon species whose index number corresponds to the index number of the Evolution stone that causes the Evolution, the game will erroneously begin the Evolution as if the Pokémon evolved after leveling up.

Some glitch Pokémon with unusual evolution flags may evolve this way according to the game 'after exposure to an item', which is not necessarily an Evolution stone.

Freezing the game in Oak's Laboratory

If the player holds "A" at the moment they interact with the Poké Ball in Oak's Laboratory, the game will be frozen until the player lets go of the button.

Hooked Dragonite glitch

The Hooked Dragonite glitch is one of several odd effects that can occur after running out of Safari Zone steps while the NPC is guiding Red to the Pewter Museum of Science. The player must first perform the Fight Safari Zone Pokémon trick and try to run out of steps as the NPC in Pewter City is guiding the player to the museum. If done correctly, the player will be teleported to the Safari Zone entrance, then upon leaving will instead be exiting from the PokéMart in Pewter City and a textbox pops up. Then they must save and reset.

Afterwards the player will find the NPC infinitely walking downwards and looping each time he goes offscreen. The player must then talk to him while standing to the left of the Pokémon Center entrance, then instead of a usual walking sequence, Red and the NPC will be indefinitely standing in place while the "follow me" music slowly fades out. Eventually this "staring contest" ends with the textbox that would've been displayed once the walking sequence ends. Closing the textbox will put the player in a battle with a "Hooked Dragonite" (hence the name) with the Gym Leader battle music, however all of the player's controls are disabled and they are soft locked.

Talking to the Pewter Museum guide at different locations will cause other effects to occur, one example includes an alternative method to walk through walls.

Causes

The first part of the glitch is caused by interrupting the walking sequence. When the NPC is spoken to, the game disables all of the player's controls and moves Red and the NPC at the same time to give the illusion that Red is following him, then once it ends, the NPC walks down to leave and the controls are returned to the player. If the walking sequence is interrupted, controls are not returned to the player, however thanks to a failsafe mechanic, controls are returned if the player enters another map. After exiting from Pewter City's PokéMart, saving and resetting confuses the game into making the NPC infinitely walk down for 256 steps instead of the usual four. Because the NPC was never intended to walk this far, the game's variables soon overflow forcing him to warp to the top of the visible area.

The effects of this glitch are caused by a buffer overflow that occurs based on the game trying to find a path for the NPC to take in order to reach the destination. The game searches player coordinates from a table to determine the various movements that can be used to bring the player to their destination, as the path is different depending on where he was spoken to. If the coordinates are not present on the table, the game searches beyond the table to find one (as the player was not intended to be able to speak to the NPC in these locations). Most of the time the game cannot find any and the game will soft lock. However if a matching entry happens to be found, the game will use it as movement data and copy it to a buffer until it reaches the first 0xFF terminator byte. The hooked Dragonite is the result of changing the address $D059, wCurOpponent, and the reason controls are disabled is because they were unable to be unlocked when the battle starts with the hooked Dragonite.

Indoor fishing oversight

In Cerulean Gym, the water tiles have wild Pokémon data programmed in, which allows players to fish Pokémon. In Pokémon Yellow, the Old Rod and Good Rod work, but the Super Rod doesn't. The bug then returned in Pokémon Gold and Silver, but it was fixed once more in Pokémon Crystal.

Lorelei's room in Indigo Plateau also has this issue, which was fixed in Yellow as well.

Invisible PC access

Celadon Hotel is based on the layout design of a Pokémon Center. In this map, if the player stands in front of where the PC would be in a Pokémon Center, the player can access an invisible PC.

There are also invisible PCs in the same position (accessible by facing up with the coordinates x=13, y=4 xblock=1, yblock=0) in Safari Zone rest houses 2, 3 and 4 (maps 223-225), but these positions are not normally accessible, so memory hacking must be done or Arbitrary code execution written using the 8F item can allow these extra PCs to be accessible without cheating.

All known invisible PCs do not exist in Pokémon Yellow.

Extra invisible PCs:

Lift Key overworld misplacement

The Lift Key glitch

In the Rocket Hideout, if the player is standing to the left of the Team Rocket Grunt who has the Lift Key and talks to him, the Lift Key will appear underneath the player when he drops it. The player can still move around and collect it if he moves downward.

This glitch was fixed in Pokémon Yellow, due to the Grunt automatically dropping the Lift Key as soon as he is defeated.

Lift goes to the same floor

In any lift of Pokémon Red/Blue/Green and Yellow, if the player chooses to go to the floor they're already on, the lift acts like it is moving.

New-game Nidorino cry oversight

During the new game tutorial, the game shows Nidorino's sprite but plays Nidorina's cry.

Oak Poké Ball delivery text overlapping

If the player has no new Pokémon registered as caught in the Pokédex (by only having the starter Pokémon) and/or no Poké Balls in his Bag (this includes buying/finding/obtaining any and then selling/tossing/depositing them) after defeating the rival on Route 22, Oak will give five Poké Balls to the player after being talked to. During this event in the English versions, one of the lines of his dialogue appears over the previous line, instead of on a new one.

This glitch occurs in all localizations of Pokémon Red and Blue and in the European localizations of Pokémon Yellow. In the Italian Pokémon Red and Blue, there's also a word in this dialogue that overlaps the right border of the text box. In English Pokémon Yellow, it was fixed but the dialogue contains a typo instead.

Overworld sprite misplacement

If the player does not have the Secret Key to the Cinnabar Gym, and surfs on the east coast and returns to land directly in front of the Gym, a man will appear on the roof of the Gym.

A similar effect happens if the player walks into the Vermilion Gym, walks directly left and then up so that they are facing the bottom-left trash can and press A to inspect it, or if the player is in the gate to Cycling Road. One of the Trainers in the Gym will be misplaced and return to his usual spot once the text box disappears, and when in the gate there may be a man standing on an object somewhere behind the guard.

Both of these variations of this glitch were fixed in some European releases of Pokémon Red and Blue, such as the Spanish version, and in all releases of Pokémon Yellow.

Pewter Gym skipping

Main article: Pewter Gym skip glitch

Trade palette glitch

If the player sees the data of any Pokémon, the palette will change its colors depending on the color of the Pokémon and the HP it has at the moment. This bug was fixed in Pokémon Yellow.

English versions only

Fight Safari Zone Pokémon trick

Main article: Fight Safari Zone Pokémon trick

Instant Text trick

If the player goes into the Cerulean City Bike Shop without a bike voucher and cancels out exiting the shopping menu of the bike shop, the game never resets a text based flag. Instead of the game showing all the text character by character, it will instead now show all text on screen instantly. Going back to the shop later and buying the bike will reset the flag.

Old man glitch

Main article: Old man glitch

Japanese Red and Green

Binding move wrong side fainting glitch

This glitch was introduced in the later revision (v1.1) of Red and Green and seemingly does not occur in the v1.0 release. It was fixed in the English Red and Blue.

When the player's Pokémon is immobile due to being trapped by the opponent's binding move, but the opponent faints due to burn or poison, then the player's Pokémon will faint in addition to the opponent's Pokémon. This does not occur if the player's Pokémon is the one using the binding move. Despite the player's Pokémon fainting, it will still have full health on the Pokémon menu.

In a link battle, because the Pokémon is only considered to faint on its Trainer's side of the link and not its opponent's side, it can cause a communication error.

Broken hidden items

Main article: Broken hidden items

In Pokémon Red and Green, there are six hidden items that do not function correctly. These hidden items are believed to have been fixed in Japanese Pokémon Blue and later versions (including the localized versions of the Generation I games).

Picking up one of these six specific hidden items causes the other five hidden items to disappear. If the player hands over a Fossil to the scientist in Cinnabar Island's Pokémon Lab (even if they choose not the revive it), all six hidden items reappear.

The broken hidden items cannot be detected by the Itemfinder. Instead, five of these six items have another set of coordinates that the Itemfinder believes them to be located at instead, although there is no item hidden at that position.

Fainted lead experience oversight

	This glitch is in need of research. Reason: Multiple fainted lead Pokémon, other versions You can discuss this on the talk page.

Before starting a Trainer battle, if the lead user Pokémon is fainted, the Pokémon sent out following it will receive half experience, even though the fainted Pokémon did not participate.

Saffron Gym glitches

Losing to Sabrina in the original versions and returning to the Saffron Gym, will cause the player to receive the post-victory text, TM46 and the Marsh Badge.

After the battle, if the player exits the last text box before returning to the overworld with B, and immediately holds A, Sabrina's before battle text will run again, allowing the player to rematch Sabrina indefinitely.

Japanese Red, Green, and Blue

NOTE: The following glitches affect all Game Boy versions of Pokémon Red and Green (1.0 and 1.1) unless noted otherwise.

Articuno binoculars cry glitch

This glitch involves listening to the cry of the Articuno in the binoculars on the second floor of the gate on Route 15. Listening to it in succession many times can corrupt the cry.

Empty Pokémon List

If the player withdraws the Potion from the PC at the very start of their adventure (meaning before they receive their starter Pokémon) and then attempts using it, an empty Pokémon List will appear and the Potion can be used, albeit to no effect. This was fixed for international releases and Pokémon Yellow, which will state "You don't have any^RB/a^Y POKéMON!" (Japanese: ポケモンが　1ぴきも　いない！).

Full Box glitch

If the player has six Pokémon in their party and all full Pokémon Storage System Boxes before watching the old man's catching demonstration, the game will state that the box is full when the old man tries to capture the Weedle. The game will try to use the Poké Ball again infinitely afterwards, and every attempt results in this message causing an infinite loop. This forces the player to either reset the game or turn the power off. This is because the game thinks that the player is catching a Pokémon, even though it's actually the old man, the game produces a "temporary" Pokémon to hold, and if the catching demonstration ends, that caught Pokémon is deleted.

This glitch was fixed in the Japanese version of Pokémon Yellow and in the localizations.

Pokédex glitch

In all Japanese Generation I games, if the player evolves their starter Pokémon before bringing Oak his parcel, Oak will assume the player already has the Pokédex and will offer to rate it instead of accepting the parcel. This prevents progression in the game, as the old man will not move until the player delivers Oak's parcel. The player will also be unable to buy items in the Viridian City Poké Mart (because the player is required to deliver the parcel before buying any items).

Select glitches

Main article: Select glitches

Dokokashira door glitch

Main article: Dokokashira door glitch

Second type glitch

Main article: Second type glitch

Silph Co. elevator entry swapping

It is possible to swap the positions of the elevator destinations in Silph Co. with the SELECT button as if they were items. Doing this in certain ways can change the list type in at least one way (i.e. to a list of 'boxed Pokémon') and corrupt data.

This glitch works in the Japanese Pokémon Blue but the effects differ from Pokémon Red and Green.

Swift effect glitch

Swift was designed to never miss, but due to a programming error in Pokémon Red, Green and Blue (as well as all known revisions of Japanese Yellow), the move is capable of missing under certain circumstances (i.e. if the foe has raised evasion, or is under the invulnerable stage of Fly or Dig or possibly from 1/256 miss chance that affects other 100% accuracy moves) unless the foe has put up a Substitute.

This was amended in the English versions, which have Swift never miss (including when a Pokémon is under the invulnerable stage of Fly or Dig) regardless of whether the foe has set up a Substitute or not.

Whirlwind text box overflow

In these games, if a Pokémon uses Whirlwind on a Pokémon with 5 characters in its name, the exclamation mark character overlaps with the border of the text box. This was corrected in the Japanese version of Pokémon Yellow with the addition of a line break.

Yellow

NOTE: The following glitches affect all Game Boy versions of Japanese Pokémon Yellow (1.0 to 1.3) unless noted otherwise.

Delayed Pikachu follow

	This glitch is in need of research. Reason: No reason specified. You can discuss this on the talk page.

In Pokémon Tower, if the player steps on the purified zone with a fainted Pikachu, and quickly pushes (B) and takes two steps, Pikachu will not match the player's first step until the player takes their second step and will continue to follow at a delay. As a result, Pikachu may end up a space distant from the player or overlapped with them. Walking back onto the purified zone while overlapped will return Pikachu's position to normal, regardless of speed.

Thanks to the Pikachu off-screen glitch, it can be done everywhere.

Freezing Pikachu

If the player jumps off a cliff when Pikachu is dancing, the Pikachu's sprite will be frozen for 7–8 seconds.

NPC over the grass

In the Viridian Forest, there is a Lass whose sprite is clearly over the grass. This trainer won't move because she doesn't have a range at which she will walk up to the player, so she has to be battled by walking up and talking to her.

Friendship item effect

This causes a no-effect item to still increase Pikachu's friendship value. For example, attempting to use a Potion on a Pikachu that has fainted or has full health, an Antidote when Pikachu is not poisoned, Calcium when Pikachu has already reached its maximum Special stat experience, or X Special when the Special stat has already been raised 6 stages in battle. This does not consume the item, so the same item can repeatedly increase Pikachu's friendship.

This glitch was fixed in Generation II.

Pikachu off-screen glitches

With the use of in-game event that causes a walking Pikachu to stay (Pikachu being put to sleep by Jigglypuff in Pewter City's Pokémon Center, Pikachu meeting Bill at Cerulean Cape, Pikachu falling in love with Clefairy at the Pokémon Fan Club) one can bring the walking Pikachu off the screen and cause memory corruption glitches such as a forced Glitch City and causing NPCs to turn when they shouldn't, or even having their save file deleted.

For each step Pikachu is off the screen, a memory address is corrupted from D437 and onward, and the values depend on where the player steps, with south being 01, north being 02, west being 03 and east being 04. Through this, the player can make Pikachu's happiness one of these low values, cause a Glitch City and through specific movement, set the play time to 255:59.

In addition to use an in-game event that causes Pikachu to stay, Pikachu can also be forced off the screen with a certain Glitch City such as Sea Route 20's Safari Zone exit Glitch City, or specific glitch items, including the glitch item “Lg-” (hex:6E) and “Rival's” effect/“Jack” effect glitch items such as “E tE” (in Red/Blue) or “o” (in Yellow); hex:94.

With more advanced applications of the glitch, it is possible to max out Pikachu's happiness or cause it to do one of four special actions (winking, the fishing action, the confused action or the 'disapproval' action) when the player character talks to it. Arbitrary code execution is also possible by creating a specific glitch sign in the Pokémon Fan Club.

All glitch items are available with the item underflow glitch. Lg- is also available through pPkMnp' ' (Ditto glitch Special 194) converting a Super Rod when it is the fifth item.

Through an in-game event that causes a walking Pikachu to stay:

Through a Glitch City and glitch item:

Pikachu off-screen text box arbitrary code execution:

Glitches involving communication with the Generation II games

Time Capsule exploit

Main article: Time Capsule exploit

Trade evolution learnset oversight

Generation I Pokémon that can evolve by trading can be taught glitch moves through this glitch. This can be achieved by trading a trade evolution Pokémon from a Generation I game to a Generation II, at a level where its evolved form will learn a move not in Generation I. Trading the Pokémon back to the Generation I game will cause that move to become a glitch move.

For example, trading a level 34 Graveler from Pokémon Red to Pokémon Gold will make the Graveler evolve into Golem. Since it is level 34, it will learn Rollout. If it is then traded back to Pokémon Red, it will still have the move, but the game won't recognize it properly since it is a Generation II move, so it will become TM05.

Glitches involving communication with Poké Transporter and Pokémon Bank

Pokémon Bank hex:FF glitch Pokémon glitch

	This glitch is in need of research. Reason: Test other glitch Pokémon. Check if there are other ways to prepare the box. You can discuss this on the talk page.

If a player attempts to transfer a Box 1 that has one Pokémon, an 'M (00) or 3TrainerPoké $ and eighteen Pokémon (in that order) through Poké Transporter and a 3DS Virtual Console versions of Red, Blue and Yellow, the Generation I game will be left with one 'M (FF) or Q ◣ which is an unstable hybrid Pokémon of 'M (00) or 3TrainerPoké $ with a blank OT, ID of 00000 and no moves.

This Pokémon can be used for the Pokémon merge glitch unless stabilized through Day Care back into 'M (00) or 3TrainerPoké $.

References

This glitch Pokémon article is part of Project GlitchDex, a Bulbapedia project that aims to write comprehensive articles on glitches in the Pokémon games.