Twice during this episode, the song "Tubular Bells" plays in the background. This 1973 song by Mike Oldfield was the theme song to the movie The Exorcist.
The scene showing Father Westley walking up to the residence at night through the gates, surrounded by fog, with a satchel and hat, prior to performing the exorcism, is an almost exact replica of the scene pictured on The Exorcist (1973) film poster.
Spot the pineapple: Agatha posted a pineapple photo on her profile. And the classic Henry's wooden pineapple is seen in his living room.
Ray Wise, the actor who plays Father Westley, has two previous roles dealing with the devil and possessions. In Reaper (2007), he played the Devil. In Twin Peaks (1990), he played Leland Palmer, who was possessed by BOB (a demon).
Lucy, at one point, states in German "jeden tag triffst du einscheidugen die dein leben verandern konnen". This translates to "every day you meet decisions that can change your life".