CaseOh, the American variety streamer known for his loud reactions and horror game marathons, turned his hatred of mayonnaise into a running joke across his Twitch streams. Clips of him spotting mayo on a sandwich and erupting into the 'NO MAYO' shout spread across TikTok and YouTube edits, where fans remix it over unrelated fails. The bit works because his outrage is total and sincere, and years after it started, creators still reach for it whenever food content goes wrong.