Vanessa Carlysle. Basically another form of Mystique. She could shapeshift all the same, but with one advanced difference. If she made contact with the person she could also replicate their powers, skills, and even their memories. She had her powers advanced by Mutant X, which caused her to begin losing her own memories and caused her inability to maintain solid form for too long. She originally debuted in New Mutants, but made her first physical appearance in X-Force. She even had a measure of a relationship with Deadpool at one point. I know most prefer her Age of Apocalypse look, but I wanted to make her as she appeared in the regular universe.