“Nani” is the Japanese word for “what,” and its dramatic anime delivery became a long-running reaction meme online. This type of shout spread through anime clips, remixes, and short-form edits, where creators used it to exaggerate confusion or disbelief. Over time, it became a recognizable audio cue even for people who do not watch anime regularly. It still shows up in reaction videos, compilations, and parody edits because the meaning is immediate and the performance is so exaggerated.