7PkMnv is a Glitch Pokémon which appears as a Tentacruel. It cannot be captured by any in-game methods, and can only be captured using GameShark or a similar cheating device. 7PkMnv is exclusive to the Red/Blue versions -- if it were traded to the Yellow version, it would become a Pokémon called 4,ゥ.
7PkMnv has been seen fairly frequently in the party of some Glitch trainers -- some GameShark codes will result in a trainer appearing who uses 7PkMnv in battle.
7PkMnv is only known to appear in Pokémon Red and Blue; its decimal number is 221 and its Pokédex number is 73. Upon leveling up, it learns several Super Glitch attacks.