Mystique (real name Raven Darkhölme) is a character from Marvel Comics and appears mostly in X-Men comics.
Mystique is a mutant, a shapeshifter able to mimic any person perfectly. She is typically a villain and foe to the X-Men.
She has been portrayed by Rebecca Romijn and Jennifer Lawrence in the X-Men movies.
Here is some of my favourite pictures of her from over DeviantArt. Check them out and show them love.