The effect comes from The Battle Cats, the tower defense game by PONOS where cat units have a chance to deal critical damage for much higher damage than a normal attack. That mechanic made the hit instantly recognisable to players, and the short clip later spread beyond gameplay into soundboards, meme edits and fan videos. Because it is so brief and distinct, creators borrow it for other games and real life clips, using the familiar clang to signal that one hit mattered more than the rest.