The Knocker

You've downloaded a horror mod for Minecraft. The mod itself features a Knocker. Knocker is a guy (or maybe a monster) dressed entirely in black and wearing a black hood. He usually stalks you or does nasty things to you, like stealing food from a chest or other resources, setting your house on fire, knocking on your door, suddenly teleporting, scaring you, and then disappearing. He's actually very strong and can easily beat you up, but... For some reason, he's never hit you since the very beginning of the game.

You were transporting iron one evening, as usual, after digging in the mines. Tired, you were sitting on your bed, petting your cat, when someone knocked on your door.