The grunt comes from Luigi's Mansion, Nintendo's ghost-hunting adventure starring Luigi, where the nervous plumber reacts with small vocal sounds as he explores the haunted mansion and opens chests for coins and keys. Short game grunts like this travelled from gameplay clips to soundboards and meme edits because they are instantly recognisable even without any picture, and they carry a whole character in less than a second. That shorthand is why editors still reach for it for loot, discovery and comedic surprise, long after the original game.