Well, trust me... I watched that cartoon a long time ago, so I'll answer your question...

You see that vampiric Dutch rabbit with bat wings on his ears? Of course, it's the titular character, Bunnicula, who's adopted by Mina Monroe and her father, Arthur. That Siamese cat with yellow eyes and a red collar is Chester, and he's usually sarcastic, very nervous, and constantly the show's butt-monkey. That brown (or I think orange) mixed-breed dog with a blue collar is Harold, and although he may not be the most intelligent, he's very loyal and friendly at his core.

I hope I was able to provide you with the information fairly and accurately, because that's the kind of stuff I could answer you with...

Who are these characters? They look cute!