Speaking about the film's influences, Daniele Massaccesi, who was part of the crew, stated that, ""Castle Freak" is full of Lovecraftian references [...] although the director may argue this point of view." Gordon stated that both himself and screenwriter Dennis Paoli took influence from the short story "The Outsider". The story involves a man leaving his dungeon for the first time in years; everyone he meets flees in terror, and he eventually sees his own distorted body after finding a mirror.