- Keep Circulating the Tapes: For a while, the only official home release the series ever saw was when it was added to Hulu streaming in 2014, but sadly was removed shortly after. However, in 2019, the entire series officially saw release to a DVD set.
- Pop Culture Urban Legends: It's been long rumored that this show was meant to be an Animated Adaptation of Doctor Who, with the Happy Days characters shoehorned in when they couldn't get the license, and Cupcake and Mr. Cool acting as Captains Ersatz of the Doctor and K-9. According to the show's developer Duane Poole, that was never the case, and it was intended as a Happy Days spin-off from the start.
- Role Reprise: Ron Howard and Donny Most voiced Richie and Ralph, respectively, after both actors had already left the live-action show. And, of course, Henry Winkler as Fonzie.
- What Could Have Been:
- Preliminary ads in comic books of the era suggested that Potsie was supposed to appear in some capacity. Ultimately, he never showed up.
- Following the series' cancellation, a spin-off that would have teamed animated Fonzie with Scooby and Scrappy-Doo was kicked around. Fonzie (and Mr. Cool) instead eventually wound up costarring in the second season of Laverne and Shirley in the Army, an animated adaptation of Happy Days spin-off Laverne & Shirley.
- Early model sheets◊ revealed Mr. Cool was originally going to be named Chopper.
Trivia / The Fonz and the Happy Days Gang