This sound is tied to CaseOh, a creator whose reaction moments are widely clipped and reposted across short-form meme pages, streams and compilations. “What is that” spread because the line is simple, instantly readable and easy to drop over almost any strange visual. It often appears alongside other exaggerated reaction staples like bruh or goofy ahh sounds when editors want a louder comedic payoff. The clip stays popular because it fits gaming fails, cursed images, awkward outfits and chaotic reveal edits without needing much setup.