The phrase combines bruh, a long running slang expression of disbelief, with what the hell boi for extra emphasis and a deliberately casual delivery. Clips using this wording spread through short form video, gaming edits and reaction posts, where the sound became a reusable shorthand for confusion. Its popularity comes from how specific the intonation feels while still fitting almost any baffling moment. Creators keep reusing it because the line is instantly quotable, easy to recognize even out of context, and short enough to loop or layer over visual jokes.