Although the Winchesters know James from a previous case, James Frampton never appeared in a previous episode.
We learn that Dean is allergic to cats.
The building facade used for the witches' club is the same facade used for Paddy's in It's Always Sunny in Philadelphia (2005).
The cat familiar that Dean is introduced to in the witch bar is named Philippe Lechat, which means "the cat" in French. This is a shout out to the Belgian comic Lechat by Philippe Geluck.
Spencer refers to James' relationship with Portia as being all "Bella and Edward". This is a reference to the protagonists of the wildly popular Twilight series of books and novels. The Twilight movies were filmed in the lot right next to the Supernatural lot in Vancouver.