This sound comes from the Zombies mode in Call of Duty, where each new round increases enemy pressure and tension. Players have heard round transition cues across multiple Zombies entries, making the sound instantly recognizable within gaming culture. It spread beyond gameplay through YouTube montages, Twitch clips and short-form edits where creators use it as shorthand for escalation. The reason it still works so well is simple: even without visuals, many players immediately understand that a tougher wave has just begun.