X2: Magneto's henchwoman, she is a shapeshifter. Mystique is blue, naked and covered in scales, and she acts as a spy. She injects a prison guard with metal, with which Magneto makes his escape, and also sexually tempts Wolverine.
X-Men: The Last Stand: Magneto's blue-skinned right-hand woman can shapeshift to match anyone's appearance as well as fight with incredible agility and strength.