Are we speaking of films only? If not, I think the game "Slender: The eight pages" was pretty intense.
As for films, I'd say nothing was (or ever will be) as scary as Jaws, seen at the age of ten, just before the summer.
I know what you're thinking. "Did he prepare six Explosive Runes this morning or only five?" Well, to tell you the truth, in all this excitement I kind of lost track myself. But being as this is the 3rd level spell Explosive Runes, the most powerful Abjuration in the world, and would blow your head clean off, you've got to ask yourself one question: Do I feel lucky? Well, do ya, punk?