This sound comes from Fortnite, Epic Games' battle royale title that became a huge online culture reference after its 2017 rise in popularity. The knocked cue is associated with the game's downed state in squad-based matches, so viewers instantly read it as losing a fight without being fully out yet. It spread through gameplay montages, streamer clips, and short-form memes because it is brief, recognizable, and easy to sync with visual wipeouts, failed flexes, and abrupt momentum swings.