Bad Education - Rotten Tomatoes
Alma movie: The Harry Potter series (2002-2011)

A tricky adversary for Harry Potter at Hogwarts but also one of the more complex characters, Snape's control of -- and later defense against -- the Dark Arts makes him a formidable opponent and one very bad teacher, indeed. Still, Dumbledore trusted him, but we'll have to wait to see just which side he ends up on...