If you’re looking for a good scare in Minecraft, you might want to check out The Librarian, a custom map that makes Herobrine something to be feared again, rather than the joke he has become. The premise is pretty simple – you wake up in a library with no idea how you got there and no clue where to go, but with the strong conviction you must get out of the place however you can. The map comes with its own custom resource pack and a number of jump scares, though it isn’t all cheap thrills. There are instructions, hand-written notes and other things to be found that add depth to the map.
Crawling around in the dark is dangerous enough when you’re in an unfamiliar place, but when there are terrors lurking just out of sight, terrors that would happily beat you to death, that tends to increase anxiety levels by a bit. The Librarian map should keep you busy for a few hours if you can manage to play through it all in a single run. Because of the way it was designed, it doesn’t really have much replay value; once you beat it you know where everything is and subsequent playthroughs go much faster.