The Horror Challenge,
A horror movie that gives you nightmares.
I almost never have nightmares from a movie I've seen, but I remember, when I was really little and Donnie Darko just came out, I watched it with my parents and I had so many nightmares about the bunny suit man. Another movie that gave me nightmares when I was little, is Mars Attacks. Which isn't even a horror movie, but I was really freaked out by the aliens.