American Horror Story Best Moments of Season 2

We get to see very little of the real Sister Mary Eunice before a demon enters the asylum (via a possessed teen) and takes over her body. Though not everybody notices at first, her change in behavior tips off the majority of the staff when she aggressively comes onto Dr. Arden, conspires to perform a coup d'état at Briarcliff, and fatally stabs Sister Jude's Nazi-hunter detective.