The cow moo became a recognisable internet joke after Doja Cat released her playful viral song 'Mooo!' in 2018, in which cow imagery and mooing were central to the humour. Clips echoing that joke spread through TikTok, YouTube Shorts and meme edits, where a single moo could turn an ordinary moment into a punchline. The sound has stayed in use because it is short, instantly recognisable and easy to place over costumes, reactions and animal-themed jokes without needing any explanation.