The phrase combines Spanish yo que se, meaning I do not know, with the English word brother, a mix common in casual online speech. Shared as a short meme audio on soundboards, it spread through reaction edits and chats where a verbal shrug works better than a real explanation. Its appeal is the contrast between the question and the relaxed answer, which makes it reusable for school, gaming and everyday confusion without needing any visual context to understand the joke.