The alert cue comes from Metal Gear Solid, Konami's stealth game released for PlayStation in 1998 and directed by Hideo Kojima. In the game it plays when guards detect Solid Snake, paired with the red exclamation mark that became one of gaming's most recognisable symbols. As clips moved from forums and early YouTube to modern short form video, the sound escaped its source and became shorthand for being spotted. Its brevity and instant recognition keep it in constant use by editors who need a discovery joke understood in half a second.