After you beat Pokémon Tower in Lavender, you have a mandatory fight against Mr. Fuji. The battle is held at the town plaza with a massive statue of Mewtwo. Mr. Fuji gives you a Mewtwo he once gave birth to, while Fuji chooses Mewtwo as his partner. Fuji's Mewtwo megaevolves into Mega Mewtwo X while player can megaevolve into Mega Mewtwo Y. After winning you get both Mewtwo's permanently. They're level 75 and know Psychic, Recover, Giga Impact and Volt Tackle.
