sentences:  Supporting characters include Irwin (Vanessa Marshall), a nerdy awkward boy who has a crush on Mandy; Harold (Richard Steven Horvitz), Billy's father who is even dumber than his son; Gladys (Jennifer Hale), Billy's loving yet mentally unstable mother; Mindy (Rachael MacFarlane), the snobby, stuck-up, and spoiled queen bee of Billy and Mandy's school; Sperg (Greg Eagles), the local bully who has a sensitive side; Fred Fredburger (C. H. Greenblatt), a simple-minded, irritating underworld creature who loves frozen yogurt and nachos; Dracula (Phil LaMarr), a selfish elderly vampire who is revealed to be Irwin's paternal grandfather in the final season of the show.The show lacks continuity for the most part, as many episodes end with characters killed, exiled, or stuck in a situation.Characters sometimes display an awareness of some events from previous episodes, but there are no clear character arcs or coherent plot lines tying the show together.