The exact source of this “what is that” clip is not clear from the available information, but it is widely used online as a reaction sound for confusion and instant disbelief. Short vocal reactions like this spread easily on meme pages, repost accounts, and edited videos because they are easy to recognize even out of context. Its staying power comes from how flexible it is: creators can drop it over awkward reveals, odd sound effects, or visual punchlines in the same way they use a bruh or a buzzer.