Call of Duty's Zombies mode, first introduced in World at War in 2008, turned cooperative survival against waves of the undead into one of the series' most recognisable modes. Its growls, screams and sudden yells became part of the mode's tense atmosphere, and clips of those sounds spread through gameplay videos, montages and short-form edits. Players still reuse this yell because it instantly signals danger and chaos, even without any visuals, making it a quick shorthand for a zombie attack in gaming content.