The Reaper horn comes from Mass Effect 3, released in 2012, where the Reapers are a race of colossal sentient machines returning to harvest advanced civilisations. Their deep horn is used in the game to signal their arrival and the scale of the threat facing Commander Shepard and the galaxy. Clips of the sound spread through gaming videos, edits, and meme compilations, where its instantly recognisable dread made it a shorthand for something unstoppable approaching, and it remains a popular dramatic cue for creators today.