A Pup Named Scooby-Doo

The Babysitter from Beyond (1x6)

Air date: Oct 15, 1988

Scooby and Shaggy go to see a scary film while dropping off Shaggy's baby sister at the sitters, but they are horrified when they find the sitter is hideous. What's worse is that the monster movie character has come to life and an escaped convict is on the loose.