Roberto Carlos is one of Brazil's most famous singers, known for decades of romantic ballads and polished live performances, which is why a brief moment of him swearing on stage circulated so widely online. Shared as a short viral clip, it became a reaction sound on meme pages and in short videos, where the surprise comes from hearing such a controlled performer lose his composure. It remains in use because the clip is instantly recognisable to Brazilian audiences and needs no explanation to land as a joke about anger or frustration.