The sound is built around the Japanese word "nani," which means "what?" Online, it became a widely used anime reaction clip in meme culture, especially in short edits where creators need an instant cue for confusion or shock. Its popularity comes from how quickly the delivery communicates disbelief, even to viewers who do not know Japanese. It remains common in reaction compilations, gaming edits and absurd meme posts because the setup is simple and the payoff is immediate.