Mewtwo

Scientists, who manipulated the DNA of Mew, genetically created Mewtwo. In "Mewtwo Strikes Back" the powerful Mewtwo summons the best Pokemon trainers in the world to test their skills against his cloned Pokemon. Pokemon battle Pokemon clones, until Mew arrives to face Mewtwo. Ash leaps between the two Pokemon in order to save everyone, but dies trying. When all of the Pokemon begin to cry, their tears magically bring Ash back to life!

First appearance: Pokemon The First Movie: "Mewtwo Strikes Back"