The sound comes from Squid Game, the South Korean Netflix drama first released in 2021. In the opening game, Red Light, Green Light, the giant doll Young-hee sings the Korean phrase for the game while players race toward her, freezing whenever she turns around. Clips of the song spread quickly on TikTok and YouTube after the show became a global hit, often reused in edits, parodies and Halloween content. It remains popular because the tune is instantly recognisable and immediately creates a sense of playful danger.