The sound comes from Cheer Up, the 2016 title track by South Korean girl group TWICE, where the shut up baby hook became one of the song's most quoted English lines. As Cheer Up spread through K-pop fan edits, dance covers and short form video, that brief vocal moment was clipped on its own for reactions and memes. Its continued use is less about the full song and more about how quickly the line communicates playful attitude, making it a staple snippet for TWICE fans and K-pop editors online.