Burro ou demente is a short Portuguese phrase that circulates as a reaction sound in Brazilian meme culture, where burro is slang for dumb and demente suggests someone acting crazy or unhinged. Rather than coming from one widely documented scene, it works because the two-word choice feels like a running joke: whatever just happened, the speaker can only be one or the other. That simple, reusable insult structure has helped it travel across short videos, edits and soundboards, where creators reuse it whenever a moment is too foolish to need a longer explanation.