Nosferatu

This one's silent and over a hundred years old, and it still works in a way plenty of modern horror doesn't bother trying for. Count Orlok isn't a suave gentleman in a cape. He's shadow and stillness and a presence that's wrong in a way I can't quite explain if you haven't seen it, and what he brings with him is worse than himself: the plague, spreading through the town behind him.

The scare here isn't jump scares, because it's 1922 and nobody's invented those yet. It's dread that builds like a smell you notice before you notice you're noticing it. A shadow climbing a staircase where no one seems to be walking. It gets under your skin and stays there.

Watch it properly dark, properly quiet, maybe with a cup of tea gone cold beside you because you forgot about it. It rewards patience rather than punishing you for having any. If you've only ever known vampires as broody romantic leads, this is the corrective. Orlok is the thing under the bed, not the one asking you to prom.