The Insta-Kill power-up comes from Call of Duty's Zombies mode, where it drops from defeated zombies and makes every weapon kill with a single hit for a short period. Players quickly learned to save it for tight rounds, and clips of its distinctive chime spread through gameplay videos, montages and streams as shorthand for a sudden power spike. Because the mode has remained popular across later Call of Duty releases, the sound still works as instant recognition for fans, even in short edits and memes far removed from the original match.