MUGEN is a long-running fan-made fighting game engine that lets players build rosters from characters drawn from many different games and series, and this parry effect is one of the shared defensive sounds used across custom creations. According to its published description, it appears with characters such as Morrigan, Yoko Littner and Franko Pedalovsky, which helps explain why it circulates beyond a single game. Fighting game editors keep reusing it because a parry is instantly readable: one clean sound tells the audience a player timed a block perfectly, without needing any explanation.