Andrew Garfield as Remus Lupin, Ben Barnes as Sirius Black, and Karen Gillan as Lily! This is literally perfect. I love how Harry Potter fans have become desperate enough for a Marauders movie that they've begun casting the movie themselves.
An American Werewolf in London (1981): This John Landis directed comedy/horror film may make you think twice before backpacking through Europe. This award-winning cult classic features a pretty graphic transformation, while being frightening and funny.