Ghoulum is a living stone statue type monster that resides in Hillhurst Mansion who often had little to say or do other than what statues do best, stand in place. While not the most active monster of Hillhurst Mansion on rare occasions he would join in on the other monsters' mischief. In one episode, he was accidentally exposed to a 'Bad Potion' turning him evil and causing him to grow into a giant under Noxic's control.