By 1985, ABC's cornerstone Saturday franchises were showing their age.
Super Friends was ending its run under the title, Super Powers Team: Galactic Guardians, becoming an infomercial, if you will, for Kenner's Super Powers line of action figures. American Bandstand, anchoring the bottom of the lineup, was nearing its end, too, and would hang on for another couple of years.
As for Scooby-Doo, however, Hanna-Barbera decided to try to cash in on the success of the feature film, "Ghostbusters", from the previous year, by having Scooby and a revamped team chasing real ghosts.
The real lure of The 13 Ghosts of Scooby-Doo, though, was horror legend Vincent Price, joining the cast as Vincent Van Ghoul, a sorcerer of some repute (rebooted as a TV horror host in the current Mystery, Incorporated series) and guardian to a street urchin named Flim Flam, who joins Scooby, Scrappy, Shaggy, & Daphne in retrieving the ghosts that Scooby accidentally loosed from the chest of demons. The show's open, narrated by Price, explains everything:
Vincent Price, of course, was hot with the kids after contributing a spoken word "rap" to Michael Jackson's "Thriller" a couple of years earlier, and pairing him with another icon in Scooby would add some more cred, wouldn't it? Unfortunately, no, it wouldn't. 13 Ghosts was cancelled halfway through its only season due to declining ratings. ABC had to accept the fact that Scooby had lost his charm after 10 years with the network. Ironically, a cartoon based on the "Ghostbusters" would replace Scooby the very next year and begin a successful 5 year run of its own.
What hurt 13 Ghosts were the absence of Fred & Velma, save for guest appearances, and a change in Daphne's wardrobe. Daph swapped her green & purple dress and purple (sometimes pink) hose for a purple jumpsuit. All she needed was a proton pack to complete a neo-Ghostbuster ensemble, but then there would've been lawsuits. Most fans, if you go by certain message boards, weren't quite so fond of Flim Flam, either.