Que isso, fi is Brazilian Portuguese internet slang, with fi used as a friendly, informal address similar to mate, and the full phrase is commonly typed when someone sees something surprising or hard to believe. Short reaction clips like this one travel easily because they need no translation of the emotion, only the tone, and they are reused in memes, reaction videos and chat replies where a spoken response feels funnier than text. The Faro label in the soundboard title helps listeners find this particular recording among many similar Brazilian reaction sounds.