Template:ElementalTypes The ???-type (Japanese: ？？？タイプ ??? type), unlike the Template:Type2, is an elemental type which existed as a non-glitch type from Generation II onward. However, no Pokémon bears this type. Pokémon eggs are typed solely with this before they hatch, and by extension, bad eggs are also of the ???-type.
Weaknesses and resistances
The ???-type has neither any weaknesses nor resistances: all damaging moves do normal damage to a Pokémon of the ???-type, and any damaging move hacked to be of the ???-type will do normal damage against all Pokémon.
No real Pokémon are ???-types; however, both eggs and bad eggs are given this type until they hatch. This can be seen in the Generation III status screen, however, in Generation II and Generation IV, egg status screens do not display type.
If a pure Template:Type2 Pokémon uses Roost, it becomes a ???-type until the end of the turn. However, all Flying-type Pokémon have two types (except Arceus which is unable to learn Roost). To obtain a ???-type, the player must change a Pokémon to be a pure Flying type (with Color Change, Conversion or Conversion 2), followed by using Roost.
The game will not allow the player to use Conversion to convert to ???-type; such as a Smeargle only knowing Curse and Conversion using Conversion with no other moves. The game will instead display "But it failed!".
Introduced in Generation II, Curse is the only move of the ???-type. Curse behaves differently depending on the type of the Pokémon using it; more specifically, if the Pokémon is of the Template:Type2, it will cut its HP in half and place a curse on the target Pokémon, while for any other type it will merely lower the Pokémon's Speed to raise Attack and Defense.
However in Pokémon Mystery Dungeon: Red Rescue Team and Blue Rescue Team, Explorers of Time, Explorers of Darkness and Explorers of Sky it is considered a Template:Type2 move, regardless of whether it is known by a Template:Type2 Pokémon or not.
There is no actual purpose in Curse being a ???-type move besides to give it a mysterious nature. If hacked to be of any other type, the move will still work as normal.
Pokémon Mystery Dungeon moves
Shadow moves are typeless moves, rendering their typing unknown.
In Pokémon Colosseum, Shadow Pokémon have the move Shadow Rush until they are purified. In Pokémon XD: Gale of Darkness, more Shadow moves are introduced. Starting in Pokémon XD: Gale of Darkness, these moves are super-effective against regular Pokémon and not very effective against other Shadow Pokémon.
These typeless moves do not run exclusively off of the user's Attack or Special Attack stat, instead depending on the move. This would later be extended to moves of the rest of the types in Generation IV.
In the main series games, ???-type offensive moves can be hacked to exist. In generations prior to Generation IV, because the ???-type is not programmed to be either physical or special, even with the highest possible base power, the move will do almost no damage.
In addition, although the actual type for the moves Hidden Power and Judgment varies, both appear as Template:Type2 moves rather than ???-type moves. Note however that as the signature move of Arceus, the type for Judgment depends on the type of plate held by the user, acting as a Template:Type2 move if no plate is held. Thus, the Template:Type2, and not the ???-type, could be thought of as the unspecialized "default" type. This re-emphasizes the possibility that Curse is considered a ???-type move for its mysterious nature rather than for its different forms when used by Pokémon of different types.
Arceus's Multitype ability allows it to change types based on which Plate it holds. Although there is no ???-type plate, the code for Diamond, Pearl, Platinum, HeartGold, and SoulSilver Versions has a sprite for ???-type Arceus. It is possible that this sprite was included to prevent the game from crashing if its base type was changed to be ???-type instead of Template:Type2.