The phrase comes from Counter-Strike's radio commands, where a player warns teammates just before throwing a grenade. It became closely tied to Counter-Strike: Source, released in 2004, as clips from matches, montages and soundboards carried the shout far beyond the game itself. Streamers and editors later reused it as a quick audio cue for danger, chaos or a joke about to land, which is why it still feels instantly familiar to first-person shooter players even outside a match.