On Earth Nineteen, Al Capone served as Vice President of the United States. This episode's title refers to the series The Untouchables (1959) and its film adaptation The Untouchables (1987), both of which concerned the efforts of the FBI agent Eliot Ness and his colleagues to combat criminals, including Capone, in Chicago in the 1930s.
Alex Désert reprises his role as Julio Mendez from The Flash (1990). After Amanda Pays (Dr. Tina McGee), Mark Hamill (James Jesse / The Trickster) and Vito D'Ambrosio (Anthony Bellows), he is the fourth actor to play the same character in both The Flash (1990) and The Flash (2014). John Wesley Shipp also appeared in both series, playing the title character Barry Allen in the former and his father Henry Allen and Jay Garrick in the latter.
Cisco speaks of a wooden barrier made of quebracha which is Spanish for an extremely hardwood tree. The name derives from "quebrar hacha" or " axe-breaker".
In the comics, Clive Yorkin was a super villain with the power to kill his victims by absorbing their psychic energy. He was featured in a story line where he was framed for the murder of Iris Allen.
When Caitlin and Julian are performing an autopsy on the chef, Cisco compares it to CSI: Crime Scene Investigation (2000). Danielle Panabaker (Caitlin) previously appeared in Play with Fire (2003).