This sound comes from Dota 2, Valve's multiplayer online battle arena game released in 2013. Players hear it when matchmaking finds a game and the ready check appears, so it became strongly tied to the suspense of long queue times ending at once. Outside the game, the clip spread through streamer edits, Discord jokes, and general gaming memes as a shorthand for a moment that suddenly demands attention, similar to how people use Mission Failed or Monster Kill for instantly recognizable game cues.