This may just be exhibit A in why ABC commissioned a Saturday morning spin-off from Happy Days.
By this point in the series, as we're in season 4, Fonzie (Henry Winkler) had become part of the core cast, and later the lead after the departure of Ron Howard (Richie). He was the one Richie and his friends went to for help every time there was a problem.
In "Joanie's Weird Boyfriend", Joanie (Erin Moran, ex-Daktari, The Waltons) tosses aside her geeky boyfriend for a gang leader, unaware of the gang's idea of initiation. Going against the advice of her parents (Tom Bosley & Marion Ross), Joanie accepts a date, which leads right back to Jefferson High. Richie decides to follow, but Fonzie has a plan, involving best buddy Carmine Ragusa (Eddie Mekka, crossing over from Laverne & Shirley).
Edit, 2/14/19: Dailymotion, due to a copyright claim from CBS, deleted the video. In its place, we have the climatic sequence.....
I think now we also know why Potsie (Anson Williams), the braver of Richie's two best buds, wasn't included in Fonz & The Happy Days Gang 3 1/2 years later. Potsie's not afraid to go to battle for a friend, but Ralph (Donny Most) is every bit the coward. Apparently, Paramount, ABC, & Hanna-Barbera saw more value in Ralph as comedy relief in animated form. Still can't get the vision out of my head of Fonzie swinging off vines and ropes to the beat of Super Friends background music......
At the time this aired, ABC already had reruns of seasons 1-3 in their weekday morning lineup before entering syndication.