The line comes from Austin Powers, the swinging sixties spy played by Mike Myers in Austin Powers: International Man of Mystery, released in 1997. Groovy, baby became one of the character's signature catchphrases alongside his other seventies slang, and it quickly entered everyday pop culture through sequels, impressions, and repeated use in comedy. Online, the short clip spread as a reaction sound for anything stylish, confident, or retro, and it remains popular because the phrase is instantly recognisable even to viewers who have not seen the films.