ゥ .4
.4 is a glitch Pokémon that can only be found by doing Method #3 of the Mew glitch and using a Pokémon with a special stat of 194. When in battle, it appears as a small floating dot and has Zapdos's cry. It is #234 and its type is the glitch type "Pokémaniac". When traded to the Yellow version, it becomes a different glitch: pPkMnp (with the #230). When its Pokédex data is entered, it will freeze the player's game.
Players are advised NOT to save this glitch to their game (or even to catch it in the first place), as it has been known to completely erase saved data IF it uses a glitch move that it knows. ([1]) Of the 24 known glitch Pokémon found in the Red, Blue and Yellow versions, it is considered to be one of the most hazardous because of this move. (See [2])
See also: Glitch Pokémon