Scooby and Shaggy head off to Dr. Phibes' lair on information that Phibes has called a meeting of the world's most fiendish fiends.
Dr. Phineus Phibes decides that as long as Scooby and Shaggy are together as a team, they can never be defeated. He devises a plan to tear them apart using a robot copy of Shaggy's first doggy sidekick "Zoinks" and Scooby's first hippy "Groovy Don".—Anonymous