Continuity mistake: Valerie wears purple shoes throughout the episode, but in one scene, she is wearing black shoes.
Continuity mistake: When Batman is talking to Scooby and the gang in the Batcave, in one shot he is missing his glove and is wearing a large ring, while in all other shots he had both gloves on.
Shaggy: Man, I don't know what's worse... Those Muck Men, or Cass Elliot's driving.
Scooby: Cass Elliot's driving!