Here's an episode of Fonz & The Happy Days Gang from November 1980.
In "King For a Day", Fonzie (Henry Winkler), Richie (Ron Howard), Ralph (Don Most), and their futuristic pilot, Cupcake (Didi Conn, "Grease"), end up in the Stone Age due to another malfunction in Cupcake's time machine.
As you'll see, Mr. Cool (Frank Welker), the pooch given to Da Fonz for this series, was meant to be comedy relief, as if they didn't already have that with Ralph. Instead, Cool cramped Fonzie's style, and, given how relationships were all but prohibited in cartoons in those days, a restriction that would fade a few years later, the writers never took the opportunity to try to pair up Cupcake with any of the three guys, especially Fonzie, who would routinely rescue damsels in distress during the course of the series. I'm still baffled by how a vine could suddenly appear in the open air without Fonzie somehow summoning one with a snap of his fingers.
Here's "King For a Day":
Like, did Hanna-Barbera really need to add another annoying sidekick character to their stable? Ehhhhh, no. I guess Cool was their way of compensating for the absence of Potsie (Anson Williams), who missed all the drama.