Movies that are . . . actually scary?

I would love a Criterion or equivalent Blair Witch release with docs and stuff detailing their efforts

As OL, points out: The Blair Witch marketing was INDEED super grassrooted and heavily, heavily seeded for longggg-game. There were a ton of early websites and other red herrings and deliberate misinformation planted all around.

I saw it on opening day lol that's how much I had bought in to the hype. Stood in line for 2 hours at an OLDE urban single-screen theater. I brought the newspaper (!) with me in line, it was the day after JFK Jr. died in his plane crash, so that was notable.