Spooktober ended two weeks ago, but I just couldn't pass this up.
The Flintstones had returned to the air with The New Fred & Barney Show, which then was rechristened Fred & Barney Meet The Thing in the fall of 1979. Two months in, The New Shmoo was shoehorned into the mix to expand the series to 90 minutes, for all the good that did, and we've covered that before.
However, NBC decided to take a chance and bring the Flintstones & Rubbles back to their primetime roots with The Flintstones Meet Rockula & Frankenstone, a 1 hour special that was never shown on Saturday mornings, though NBC, if they wanted, could have done so to spare us further embarrassment for the Thing.
Fred (Henry Corden) & Wilma (Jean VanderPyl) and Barney (Mel Blanc) & Betty attend a taping of Make a Deal or Don't, a Stone Age parody of Let's Make a Deal, hosted by Monty Marble (guest star Casey Kasem). Next thing you know, they're off on one of their strangest adventures yet.
When the Saturday morning show was tweaked again the following season, the Frankenstones were added as new neighbors, with Charles Nelson Reilly (Match Game, ex-Lidsville, Uncle Croc's Block) as the domesticated monster for comedy relief. However, after the series was cancelled, the Frankenstone family was retconned out of existence.
I didn't see the episode per se. However, the NBC affiliate could be picked up on the radio, and so I listened to the broadcast, as if it were a radio play. As I noted, it was never rebroadcast, which tells you how well it didn't do in the ratings.