Scooby-Doo on Zombie Island sequences of interplay between Shaggy and Scooby for him. After Don Messick's death, Scott Innes replaced Messick as the voice of Scooby-Doo. Casey Kasem did not reprise his role as Shaggy Rogers as he wished to only voice Shaggy if the character became a vegetarian, like himself. Instead, Billy West provided the voice for Shaggy. Mary Kay Bergman was cast as Daphne when the character was taken in a new direction. B.J. Ward, who played Velma in the "Johnny Bravo" crossover episode, reprised her role in this film. Frank Welker is the only actor from the original series to reprise
Scooby-Doo (character) for clumsiness and moments of being dimwitted as well. Different iterations of the character have been developed and expanded in the various series featuring the characters, many of them contradicting, such as the original series and recent live-action movies where Shaggy and Scooby first meet as older teenagers for the first time. This contradicts the animated series "A Pup Named Scooby-Doo", where they know each other from almost infancy, though the films may be seen as having a different continuity altogether than the cartoon products. As an adult canine, Scooby is usually treated as a mix of a pet and