The red flag meme grew on TikTok as a shorthand for warning signs in dating, friendships and work, with creators listing dealbreakers over trending audio. Pairing that idea with MC Hammer's U Can't Touch This, a 1990 hit built around a famously confident hook, gives the warning a playful, self-assured tone. The combination travelled as a short reaction sound, reused whenever a clip needed an instant, recognisable way to say no thanks and move on.