Characters played by Frank Welker
Fred Jones
Scooby-Doo
Presenter
Mecha Mutt
Characters played by Matthew Lillard
Shaggy Rogers
Characters played by Grey Griffin
Daphne Blake
Loud Speaker
Characters played by Mindy Cohn
Velma Dinkley
Characters played by Julie Bowen
Dr. Devon Albright
Characters played by Lacey Chabert
Melanie Staples
Characters played by Phil LaMarr
Stan
Mission Control
Characters played by Alan Rachins
Dr. Ned Staples
Characters played by Paul Reubens
Irv