Spooky Buddies (2011) on Netflix

Plot summary

In 1937, the townsfolk of Fernfield march on the home of Warwick the Warlock, who has taken five puppies for a sacrifice to the Halloween Hound. One of the pups, Pip, belongs to a boy named Joseph. When the hound petrifies Pip's siblings, Pip becomes a ghost. Seventy-five years on, the Buddies visit that same manor on a school trip with their owners Alice, Billy, Pete, Sam and Bartleby. Billy hears a legend that saying "Halloween Hound" three times before Warwick's mirror summons the hound. B-Dawg, called a scaredy cat, wants to prove otherwise, so he goes into the condemned house and says the words. Pip's ghost appears to warn the Buddies, and the group turns to Zelda, a sorceress dog.