@Evan - A veritable shotgun blast through the windshield of your adolescent mind?
I had a few similar experiences at a young age, even with some TV shows. The "Nightmare at 20,000 Feet" episode of The Twilight Zone scared the hell out of me when I was a little kid. I also remember an episode of Amazing Stories with some kind of "guppie" monster hiding in the closet that terrified me. Even the hairy sewer monster from Big Trouble in Little China freaked me out when I first saw that movie. Really fond memories of the thrill of being that scared by something.
Nothing has ever got to me like The Exorcist though. Fucking hell.