What type is Mewtwo in the original Pokémon games?

Mewtwo is a Psychic-type Pokémon in the original Pokémon games. Pokémon Red and Blue introduced it as a Legendary Pokémon associated with genetic experimentation.

In the first games, Mewtwo can be encountered in Cerulean Cave after the player defeats the Elite Four and the Champion. Research notes in the ruined Pokémon Mansion on Cinnabar Island describe the experiments that led to its creation from the genetic material of Mew.

Its Psychic typing gives Mewtwo access to powerful moves and makes it especially strong against Fighting- and Poison-type Pokémon under the original battle rules. Mewtwo also had the highest overall base-stat total among the original Pokémon, reinforcing its reputation as an endgame challenge.

Mewtwo is sometimes confused with Mew, its genetic source in the game's story. They are separate species, and Mew is not Psychic's evolved form of Mewtwo. In later games, Mega Mewtwo X gains a secondary Fighting type, while Mega Mewtwo Y remains Psychic-type.