While it is not known to evolve into or from any other Pokémon, it can Mega Evolve into two different forms: Mega Mewtwo X using Mewtwonite X and Mega Mewtwo Y using Mewtwonite Y.
It is among the most well-known Pokémon, being the star of the first movie and, in Generation I, the Pokémon with the highest base stats. In Generation VI, Mega Mewtwo X and Mega Mewtwo Y have the highest base stats of all Pokémon. It is a member of the Mew duo along with Mew.
Mewtwo is at Cerulean Cave waiting for Fuse to attack, if the player goes to him he will say... . Later, at a higher level, the player will get a message that Mewtwo needs Mewtwonite X to defeat Fusion Mew. This will give the player the Mew Nano.
- Mewtwo is a clone.
- It was made by Team Rocket scientists before it escaped.
- Its time with the scientists made him distrust humans until Ash showed him that not all humans were evil.
- Mewtwo is considered one of the strongest Pokémon to date.