Leech

A mutant with the ability to ‘turn off’ all power around him, including mutant abilities, the X-Men, Spyke helped save Leech from a group of mutant haters. Rogue later absorbed his powers in order to stop Apocalypse.

Origin
Leech's family left him expecting him to die after his mutation manifested. He was then seen by Calibanand brought him to Annaleewho took good care of him alongside with other mutants whom she raised. He became a young Morlock. He then befriended Artie Maddicksand had some encounters with the X-Men.

Powers
Leech has the ability to negate any kind of powers no matter what its origin is, whether it is mutant or extraterrestrial power. Leech's powers were once uncontrollable and involuntary but as time passes by, he studied how to take control of this. His powers can also weaken powers and cause temporary depowerment. Some physical effects such as being thin may also occur depending on the nature of the power that he negated.