After defeating the ghost with the cursed mask, Charles tells Edwin that he might encounter a ghost who kills people by drilling into their heads. Showrunner Steve Yockey previously worked as a staff writer on Supernatural (2005). He wrote "Advanced Thanatology (2017)", which involved a ghost with a cursed mask who was killing people by drilling into their heads.
When Charles & Edwin are arguing about Crystal in the closet, most of the board games on the shelf in the background are different variations of Clue.
In the opening credits, one of the dancing skeletons does the Carlton, a dance move popularized by Carlton in The Fresh Prince of Bel-Air (1990). Then, when the team is in the malt shop, the song "It's Not Unusual" is playing very quietly in the background - the song that Carlton does the signature dance to.