missingno.

Japanese name: けつばん Ketsuban

A well-known glitch Pokémon in the Generation I games.

Its typical appearance is a mess of black, purple and orange pixels somewhat resembling a reversed "L" shape. Alternatively, MissingNo. may look like a Kabutops or Aerodactyl fossil, like the ones found in the Pewter Museum, or a Pokémon Tower ghost.

It may corrupt the saved game to some extent, including messing up the trainer image and the Hall of Fame.

Its presence causes the item in the sixth slot to be multiplied. This is sometimes done intentionally by the player, as a method of cheating to have plenty of otherwise very rare or unique items such as Master Balls and Rare Candies.