Spot the pineapple: When Henry and Madeline are in the kitchen at the beginning of the episode, right after Shawn comes downstairs, there is a pineapple on the table as Henry is opening a bottle of wine.
Shawn's mom Madeline says that she met Henry because he twisted his ankle at the cinnamon festival. The episode "Dual Spires", their "Twin Peaks" episode, involves them going to the cinnamon festival.
Cybill Shepherd makes her first appearance in this episode as Shawn's mother, 'Madeline'. Shepherd previously starred as a character with the same name in "Moonlighting." A show in which her character was part of a private detective agency.
SPOT THE PINEAPPLE: When Lassiter is being interviewed by the psychologist in Chief Vick's office, the main body of the lamp on the end table behind the psychologist is shaped like a pineapple.
When Gus says, "the call is coming from inside the house", this is an allusion to the move "When a Stranger Calls" which famously had the same line of dialogue. This is also an allusion to the movie "Black Christmas", a mystery/slasher movie from 1974.