The pop comes from Bloons Tower Defense, the tower defense series by Ninja Kiwi in which players use monkey towers to burst waves of coloured balloons called bloons. The sound is heard every time a dart, bomb or other projectile bursts one, so long-time players associate it with steady progress through a round. Clips from Bloons TD 5 in particular circulated on gameplay videos and soundboards, where editors reused the short burst as a reward cue. It remains popular because it is instantly recognisable to fans and fits neatly into memes, edits and reaction clips.