Eric Roberts and Lance Henriksen are both known for playing psychopaths, which adds to the mystery element of who the killer is.
Eliza Roberts, Eric Roberts' real life wife, played the diner waitress who ironically rejects his advances.
When Eric Roberts was on Howard Stern in 1994, he mentioned his movies that were coming out, not exactly plugging but reeling them off for their future unknown releases; and for Nature of the Beast he said, "Lance Henriksen is PERFECT in this."
To make him look less sinister and more of an average guy salesman from a suburban home, Lance Henriksen has a slight fake belly.
Reunites Lance Henrikson with Brion James after The Horror Show (1989).