Vampire symbolism frequently appears throughout the novel, and it represents Harold and Chester’s deepest fears. When Bunnicula first arrives in the Monroe household, Harold is afraid of how the bunny might disrupt the normalcy in the home. He sees Toby, his closest human, fighting his brother for the right to take care of Bunnicula, and he feels a pang of jealousy. Harold goes along with Chester’s vampire theory because he’s not initially sure what to believe about Bunnicula, and Chester is very convincing. It’s only toward the middle of the novel, after Harold befriends Bunnicula, that his fears about Bunnicula being a vampire fade.

Chester’s fears about the alleged vampire bunny are more persistent. He continually plots Bunnicula’s demise because he’s afraid of what the bunny might do to him, Harold, or the Monroes. He claims that he’s afraid the bunny will suck their blood like a vampire, but the veterinarian diagnoses Chester with stress caused by sibling rivalry. This means Chester was less convinced that Bunnicula would harm the family and more worried that the bunny would take the family’s attention away from him.