Proteus (Marvel Animated)
Proteus was originally Kevin MacTaggart, son of Moira and Joseph MacTaggart (though the estranged Joseph never knew he had a son). He eventually manifested the mutant power to warp reality, and Moira imprisoned him (in a cell made of metal, his only weakness) to protect him from the world and possibly "cure" him.
Proteus, as he came to be named, eventually escaped and began possessing people, terrifying people with his powers, and eventually sought out his father Joseph. He was eventually defeated by the X-Men.
- X-Men: "Proteus" (Parts 1 and 2) (1995)