The sound comes from SMG4, the long-running Mario parody web series on YouTube created by Luke Lerdwichagul in 2011, where Mario is rewritten as a chaotic, childish comic character. Fans clip his strangest lines and share them as standalone reactions detached from any episode plot. This sheep line spread in that format, joining other goofy ahh sounds passed around in gaming edits and meme compilations. It stays popular because SMG4 Mario's random outbursts work instantly, even for viewers who have never seen the original video it was taken from.