BUNNICULA seems to be a spin-off/reboot of a children's book series which ran from 1979 to the mid-2000s. An adaptation of the first book was done by Ruby-Spears in 1983, but not that many people are aware of it. You can YouTube it.
The animated series takes place in a different continuity where Harold the Dog and Chester the Cat are owned by an adorkable horror nerd called Mina, who has moved to New Orleans with her father. Mina discovers a black-and-white rabbit called Bunnicula, who she takes in as a third pet. What she doesn't know is that the rabbit is a VAMPIRE. She's safe though, he only consumes vegetable juice (carrots, onions, radishes, peppers, etc.). Each vegetable gives Bunnicula a different ability, a la A BOY AND HIS BLOB for the NES.
Not too long after Bunnicula's discovery, strange things start happening in the Big Easy: time-travel mirrors, giant cockroaches, ghostly owls in armor, alligator ghosts that influence crying, an army of undead fish, and more! It's up to Bunnicula, Harold, and Chester to prevent Mina from finding out about this weirdness.
If you liked WEIRD SCIENCE and COURAGE THE COWARDLY DOG, I'd say check it out. Bunnicula's high-pitched gibberish may irk some people, but I wasn't annoyed.
Also, FUN FACT: Chester is played by Sean "Samwise Gamgee" Astin and one of the original co-authors is a producer on the show.