was mork&mindy a spinnoff from Happy days?

I guess it could be called a spin off, but, it really just started off as a stand alone episode, but, Robin Williams performance received, positive reviews from the critics and so many letters from the viewers, that when the episode went into reruns, a new ending was tacked on, to change the episode from a fever dream of Fonzie's to an introduction to the series Mork & Mindy.

As a result of the change in plot, Mork was bought back to Happy Days for one episode, although Mork & Mindy was set in modern day 1979. This is the season that Happy Days "Jumped The Shark."

yes, it's from happy days. garry marshall's kid requested an alien and that's where the idea came from.

Didn't Mork visit Richie more than once? I remember a scene with Richie and Mork chatting like old buddies.

Didn't Mork visit Richie more than once? I remember a scene with Richie and Mork chatting like old buddies.

No it was a dream

I looked it up and Mork did return in season 6 episode "Mork Returns."