A Lua Me Traiu is a hit song by Brazilian band Banda Calypso, fronted by singer Joelma, and its chorus became instantly recognisable across Brazil. The line about the moon betraying the singer gave heartbreak a dramatic, danceable hook that radio and parties kept alive for years. Online, Brazilian users clipped the most wailing part of the vocal and turned it into a reaction sound. Shared in WhatsApp groups, edits and meme pages, the stretched traiu became shorthand for feeling hilariously betrayed by friends, luck or everyday bad news.