The sound comes from Woe, Is Me and their track Nothing Left To Lose, where the blegh is delivered as a low metalcore vocal rather than a clean lyric. In metalcore, that kind of growled interjection is used to add attitude and release after a heavy breakdown, and fans clipped it out because it works perfectly on its own. Shared through soundboards and short-form edits, the extended version became a handy reaction clip for disgust and dramatic failure, keeping the band's aggressive vocal style alive in meme culture long after the original track.