This sound comes from ALF, the American television sitcom that first aired in 1986. The title character, a sarcastic alien from Melmac, became known for his jokes, voice and distinctive laugh. Short clips of that laugh have stayed recognizable online because they instantly signal vintage TV comedy. People still use it in meme edits, reaction posts and throwback compilations when they want an old-school sitcom feel that is lighter and more playful than a harsher reaction sound.