The phrase itself is everyday Brazilian Portuguese slang, with 'cala a boca' meaning shut your mouth and 'arrombado' adding a vulgar insult on the end. Clips of people shouting it have circulated for years in Brazilian meme culture, group chats and short video edits, where short rude audios are reused as instant reactions. Its popularity comes from how little context it needs: even viewers who do not speak Portuguese understand the anger in the delivery, while Portuguese speakers get the extra shock of the insult, making it a durable reaction clip.