Another big inspiration for this comic is the classic noir film Sunset Blvd., which takes a look back at the world of Hollywood film-making in the 1920s and twists it into something dark and disturbed. The mansion in this comic is supposed to represent something similar: a fallen empire.

The Loon's arrival at the mansion's garage is directly inspired by the main character in Sunset Blvd. approaching the run-down mansion of an aging and forgotten silent film actress. I tried to have a similar reveal here.
The exterior of the mansion is mostly inspired by the Magic Castle in Hollywood, which is a nightclub exclusively for professional magicians and stage magic enthusiasts. It only recently opened to the public, and you need to say a password to open a secret passage in order to see the rest of the building.