Frank Welker Fred, Scooby Voice Mindy Cohn Velma Voice Grey DeLisle Daphne Voice Matthew Lillard Shaggy Voice Amy Acker Nova Guest Voice Dee Bradley Baker Kriegstaffabot Guest Voice Lewis Black Mr. E Guest Voice Clancy Brown Nibiru Guest Voice Linda Cardellini Marcy "Hot Dog Water" Fleach Guest Voice Tia Carrere Judy Reeves Guest Voice Gary Cole Mayor Fred Jones Sr. Guest Voice Harlan Ellison Himself Guest Voice Vivica A. Fox Cassidy Williams Guest Voice Kate Higgins Mayor Janet Nettles Guest Voice Sam Register Executive Producer Spike Brandt Producer Tony Cervone Producer Victor Cook Director Michael Ryan Writer