I saw the Frank Langella Dracula when I was 12. It both scared me and turned me on. I think it had a profound effect on my sexuality.
As an adult, A Dark Song really scared me. It's an indie occult film.
Other movies I've found scary are:
Nightmare on Elm Street
Candyman
Event Horizon
Raw
Lots of others I enjoy but didn't exactly scare me, like Let the Right One In, The Devil's Backbone, The Wailing, Invasion of the Body Snatchers, Cat People, and Spoorloos.
Movies that can't make up their minds what kind of movies they are annoy me.
Dammit.
I said Event Horizon, but was thinking of Sunshine.
Event Horizon is trash. Great trash, but I understand why people hate it.
Oh, "Sunshine" is valid.
@tyghebright
"Event Horizon" just made me mad. A science fiction movie that turns into a haunted house movie that turns into "Prince of Darkness", oof.