The exact original recording behind this clip is not widely documented, which is common for short reaction sounds that are ripped, remixed and reposted across meme pages. Its power comes from the familiar slang itself: bruh signals disbelief in online humour, and stretching the follow-up into naaaaahhh makes that disbelief louder and funnier. As creators reused it over fails, pranks and unexpected reveals, it became a shorthand punchline that needs no explanation. That simplicity is why it still appears in edits where a quick, exaggerated reaction says more than dialogue.