10. The small town is named “Hobb’s End”, an in-joke reference to the subway station where the alien ship is excavated in the movie Five Million Years to Earth.
9. John Trent occupies cell number 9 at the asylum, and rents room number 9 at the Pickman Inn in Hobb’s End
8. The six Sutter Cane novels are: “The Hobb’s End Horror”, “The Feeding”, “The Whisperer in the Dark”, “Something in the Cellar”, “The Breathing Tunnel” and “Haunter Out of Time.”
7. At the end of the film, when Sam Neill approaches the movie theater showing the meta-film, the following credits can be seen on the movie poster outside the theater: “New Line Cinema Presents a John Carpenter Film ‘In the Mouth of Madness’ Starring John Trent, Linda Styles, Jackson Harglow, Written by Michael De Luca, Associate Producer Artist Robinson, Director of Photography Gary B. Kibbe, Production Designer Jeff Steven Ginn, Produced by Sandy King, Director John Carpenter.”
6. The dozens of monsters featured towards the end of the film were a combination of men in suits, animatronics and a full-sized “wall” of creatures. It took over thirty people to operate the monsters.
5. The Sutter Cane character is clearly based on John Carpenter’s friend Stephen King, even referencing King’s New England roots, with Hobb’s End filling in for King’s Castle Rock.
4. During the scene where a hand breaks through the glass of Sam Neill’s cell, a piece of fake glass really cut his neck
3. The car keys that Julie Carmen swallows when Sam Neill is trying to escape from town were made out of pasta.
2. After Sutter Cane says “Did I ever tell you my favorite color is blue?” it is revealed that throughout the entire movie, whenever an actor has a close up, their eyes are blue, proving Sutter Cane’s power
1. The film contains many references to H.P. Lovecraft’s stories, for example the name of the hotel and hotel owner “Pickman” is a reference to the short story “Pickman’s Model.”