30 Greatest Marvel Movie Villains
6. Mystique - Rebecca Romijn-Stamos (X-Men 1 & 3)
Mystique is by far one of the more morally ambiguous Marvel movie villains, working alongside Magneto in the original X-Men movie to repeal the Mutant Registration Act, though of course their terrorism sees them facing off against Wolverine and the other X-Men.
While Mystique and Magneto are forced to temporarily side with the X-Men to bring down William Stryker in X-Men 2 (until attempting to kill all of humanity, anyway), they're back to ambiguous villainy in X-Men: The Last Stand, fighting back against a mutant cure they fear will be used to wipe out mutant-kind.
Mystique is of course iconic due to her scaly blue skin, red hair and ability to shape-shift to resemble anyone she wishes. She's only been an outright "villain" for two of her six X-Men movie appearances, but Rebecca Romijn-Stamos absolutely killed the part before Jennifer Lawrenced showed up and made it decidedly less interesting ever since.