Scooby Doo: Mystery Incorperated Easter Egg - Hidden Hanna Barbara Characters

In the episode "Revenge of the Man Crab" (S1:E4) as the Myster Inc Gang is passing by the volleyball courts they pass a the teenage Pebbles and Bam-Bam from Hanna-Barberra's Flintstone shows. This scene is shown again in the flashback of the clues at the end of the episode.

At the end of the episode "Howl of the Fright Hound" (S1:E10) when the worker from the Animal Asylum calls the sheriff to let him know Professor Pericles had escaped, one of the workers is wheeling a handcart with a restrained Yogi Bear, another of Hanna-Barberra's legendary characters.