Horror is an expansive genre. Without breaking a sweat, it can encompass films as diverse as social parables like Get Out, sci-fi haunted houses like Alien, monster brawls like Freddy vs. Jason and harrowing family dramas like Hereditary. That can make the borders between horror subgenres a little fuzzy, but among them all, there are those that are, without a doubt, truly, brutally, horrific. We’re talking about the troublemakers, the nauseous explorations into the dark that empty festival theaters and earn zero-star reviews.