Dean suggests that the butler is acting like a Renfield. This refers to a character in Bram Stoker's Dracula (novel and films) who is a willing servant to the vampire. It has become a colloquial term in the horror industry for any character who is a fitting victim to the monster, but instead acts purposely to help them, either through love, mind control, or addiction.
There are multiple references to the board game Clue and the movie Clue (1985) found throughout the episode.
- Dean refers to two of the arguing family members as Mrs. Peacock and Colonel Mustard (at around 14 minutes).
- Each of the weapons are either found by Dean and Sam or revealed while they are in the shot: Rope (at around 17 minutes), Lead Pipe (at around 17 minutes), Wrench (at around 21 minutes), Knife (at around 22 minutes), Candlestick (at around 26 minutes), and Revolver (at around 28 minutes).
- The board game's box is seen shortly after Dean enters the attic and releases Olivia (at around 17 minutes).
- The Knife is the only weapon found or revealed initially when Dean is not in the shot (at around 22 minutes).
- Among other names, Dean called the butler "Wadsworth," the name of the butler in Clue (1985)
Dean calls Philip the butler variously Alfred, Mr. Belvedere, Jeeves, and Wadsworth. Each is a famous fictional butler.
In memory of James Ashton MacCarthy, father of episode director John MacCarthy who passed away during filming of this episode.
Kevin McNulty (Phillip) previously appeared in the season one episode Faith (2006), as Roy LaGrange.