One measure of a good horror movie is not how often you jump when the monster bangs out from behind a door, but how often you find yourself nervously peering at dark corners of the screen. It takes only a few minutes of John Carpenter’s Halloween or Kiyoshi Kurosawa’s Pulse to make you dread what might be lurking in every unlighted nook or out-of-focus background. It’s been a while since a movie made me feel that way, but David Robert Mitchell’s It Follows creates that kind of constant anxiety. Even the startling opening shot—a 360-degree pan around a normal suburban street, no monsters in sight—instills the idea that something might be there, threatening, even if we can’t see it at the moment.