Scooby-Doo the series and the billing, in an attempt to boost "Scooby-Doo"s slipping ratings. The 1979–80 episodes, aired under the new title "Scooby-Doo and Scrappy-Doo" as an independent half-hour show, succeeded in regenerating interest in the show. Lennie Weinrib voiced Scrappy in the 1979–80 episodes, with Don Messick assuming the role thereafter. Marla Frumkin replaced Pat Stevens as the voice of Velma mid-season. As a result of "Scooby-Doo and Scrappy-Doo's" success, the entire show was overhauled in 1980 to focus more upon Scrappy-Doo. At this time, Scooby-Doo started to walk and run anthropomorphically on two feet more often, rather than on
Scooby-Doo joined with a new Hanna-Barbera show, "Dynomutt, Dog Wonder", to create "The Scooby-Doo/Dynomutt Hour" (the show became "The Scooby-Doo/Dynomutt Show" when a bonus "Scooby-Doo, Where Are You!" rerun was added to the package in November 1976). Joe Ruby and Ken Spears, now working for Silverman as supervisors of the ABC Saturday morning programs, returned the program to its original "Scooby-Doo, Where are You!" format, with the addition of Scooby's dim-witted country cousin Scooby-Dum, voiced by Daws Butler, as a recurring character. The voice cast was held over from "The New Scooby-Doo Movies" save for Nicole Jaffe, who retired from acting