Scooby-Doo and Scrappy-Doo (1979 TV series) threatening cancellation for the show, whose ratings were in decline. ABC was going to choose between two shows-Scooby-Doo or an unnamed pilot from Ruby Spears Enterprises. Therefore, for its 1979–1980 season, "Scooby-Doo" was given a major overhaul, adding the character of Scooby's nephew Scrappy-Doo, voiced by Lennie Weinrib, and changing the name of the show to "Scooby-Doo and Scrappy-Doo". Although still present in these episodes, the characters of Fred, Daphne, and Velma became less essential to the plot and Shaggy, Scooby and Scrappy were the main focus. Marla Frumkin took over Pat Stevens' role as Velma Dinkley towards the end
The Scooby-Doo Show of which, "The Chiller Diller Movie Thriller", guest-starred Scooby-Doo and Scooby-Dum's distant female cousin, Scooby-Dee), plus reruns from the 1976–1977 season. The name of the block was changed to "Scooby's All-Stars" for the 1978–1979 season, when the program was shortened to an hour and a half, after the cancellation of "Dynomutt". 16 half-hours of "Scooby-Doo" (featuring just the original five characters) were produced this season, and began airing earlier in the morning before the "Scooby's All-Stars" block as a third season of "Scooby-Doo, Where Are You!" in September. "Scooby's All-Stars" instead aired reruns of the 1976 and 1977 episodes for