Henry Winkler made an appearance in the Season Two episode, "City on the Edge of Forever (Flashbacks)". He appeared as Arthur Fonzarelli, from Happy Days, as well as providing the snarls of the Big Black Scary Monster. He also appeared in the beginning of the Season Four episode, "Probably", where he is seen jumping over a shark with a motorcycle. Unlike the real Happy Days episode, Fonzie is brutally killed by the Shark.