74 years ago on Halloween in 1937, the Halloween Hound appeared in a magic mirror and agreed with Warwick's proposition to rule the land together. He uses his howl breath and sucked the souls of Pip's siblings. Afterwards, their bodies turned into stone. As Pip's soul was about to be consumed, the sun rose and it stopped the ritual from happening. With Pip staying as a ghost, the Halloween Hound had to go back to the other side of the mirror with Warwick jumping inside to escape from the sheriff.
Role in the film
74 years have passed, and after two boys went into the old manor and approached the mirror, they accidentally freed the terrifying duo, meaning that the Halloween Hound went in the real world with a physical body. After Warwick uses a potion to turn the boys into rats, he and the Halloween Hound set off to Fernfield on Halloween night. There, after seeing kids wearing Halloween costumes, he stated that the town was already taken over. Warwick tells him to go and find five puppies of the same blood needed to complete the ritual before sunrise.
Later, he finds the right souls he needed; the Buddies. He chases them all the way to Zelda's place and then the Sheriff's office. After using his howl breath to turn Zelda and Deputy Sniffer into stone, the Halloween Hound captures the Buddies at the cemetery. He then tells Hoot to inform Warwick that he captured the puppies. Hoot later releases the Buddies after they reason with him and tell him that he can reform, but then the Halloween Hound sees that Hoot betrayed them, so he turns the owl into stone.
In the manor, after Pip became whole again, Pip sacrifices himself to save the Buddies' lives. The Halloween Hound remembers him from 74 years ago and then consumed his soul. Because Pip was from the same litter, the Halloween Hound goes to the mirror and opens the portal of the netherworld, releasing evil spirits to roam around Fernfield. He was also seen chasing the rats from earlier. He decides to get the Buddies anyway and corners them in the kitchen. When he tried using his howl breath, Budderball farted strongly and successfully deflected his power against the Halloween Hound himself. He then turned into stone.
In the end, the sun rose and all who had been turned into stone were back to normal with their souls in place, including Zelda, Deputy Sniffer, Hoot, Pip and his siblings. Due to the sun being his weakness, the Halloween Hound died afterwards off-screen. Even though it was not seen, it was highly possible.
- The Halloween Hound's weakness is not only the sun, but also his own howl breath when deflected back at him.
- During the 74 years the Halloween Hound was in the mirror, he did not age whatsoever, nor did Warwick, Hoot, Pip and his siblings.