Rebecca Romijn

Rebecca Romijn (born on November 6th 1972) is an American actress and former model.

X-Men
In her first appearance in the 2000 film, Mystique (played by Rebecca Romijn) is first seen barefoot when she transformed into her original form and used her feet to knock out Senator Kelly as she and Toad takes him to see Magneto. Later she is still barefoot during her fight with Wolverine.

X2
She is barefoot after she, Wolverine and the other invade Stryker's base to save the other mutants.

X-Men: The Last Stand
Mystique use her barefeet to not only break the guards neck but to grab his keys and used her toes to unlock her cufflinks. However after being shot with the antidote she loses her blue skin and her mutant power and is briefly seen barefoot