Zombie moans have been a staple of horror for decades, used in films, haunted houses and video games to signal that the undead are nearby without showing them on screen. The sound works because a wordless groan is universally understood as inhuman and threatening, even out of context. Online, short versions like this one are widely shared as sound effects for Halloween edits, comedy sketches and gaming videos, where a single groan can set a spooky mood in less than a second. Its simplicity is why it keeps getting reused.