The exact origin of this stretched what clip is unknown, but it belongs to a long running family of single word reaction sounds shared on soundboards and meme pages. Its spaced out spelling mirrors how the line is delivered online, turning a normal question into a shorthand for disbelief. Short voice reactions like this spread because they need no context, work over any footage, and can be reused instantly in edits, streams and group chats, which keeps the whaaat reaction in regular rotation long after many longer memes fade.