Surto is Brazilian Portuguese slang for a sudden freak out or meltdown, and the word has become shorthand in K-pop fandom for an exaggerated reaction clip. This audio circulates among BTS fans as a reaction sound, shared in edits, fan cams and comment threads where a calm situation quickly turns chaotic. Its short length makes it easy to loop or drop into TikTok and WhatsApp style videos, and it remains popular because the panic reads instantly even without any visual context or translation.