Jericho's (Jake Etheridge) backing band is played by the members of the Elastic Waste Band: Tango, Sweet Johnny High-Pockets, Sir Richard Furlong and Hot Karl. EWB and the members' names were made up names used by the band Louden Swain in early Supernatural fan conventions. The members of Louden Swain are Rob Benedict, who appeared as Chuck Shurley in Supernatural (2005-2020), Billy Moran, Mike Borja and Stephen Norton.
Richard Speight, Jr. (Loki) and Rob Benedict (Tango) both guest starred in Supernatural (2005-2020) as The Trickster/Gabriel/Loki and Chuck Shurley/God, respectively, and director Amyn Kaderali directed 9 episodes of Supernatural.
Richard Speight, Jr. is reprising the role of Loki that he originated on Supernatural (2005-2020).
John tells Samuel to stop treating Mary like a soldier and more a like a daughter, yet John treats Dean in the same way in Supernatural (2005). In other words, the cycle of intergenerational trauma was never broken.