Mewtwo

Mewtwo is a character in Super Smash Flash and Super Smash Flash 2. It is a geneticaly mutated clone of Mew, created by scientists hired by Team Rocket's leader, Giovanni. After Mewtwo became aware of what was happening, he used his psychic powers to blow up the lab, killing everyone in the process. Despite his past, Mewtwo joined the Super Smash Saga as a normal fighter.

SSF2
His moveset in SSF2 is a bit different than it's Melee counterpart