Horrifido, or Fido as he was known in life, was the pet dog of the former owner of the old castle (Capt. Charles de Ghoul) where Dr. Zitbag sets up his pet shop. Initially haunting the castle as a ghost, the doctor inadvertently uncovers the dog's old bones and the ghoul reanimates them, giving him a physical form. Horrifido is thus a skeleton dog with green bat winged like ears, who becomes Dr. Zitbag's assistant. Sometimes Horrifido is seen wearing a pink bow collar around his neck.