- "I already left once before. I left both of you. Worst mistake I ever... ever made in my entire life. Wasn't gonna make that again. Family shouldn't leave family. I'll always love you"
- —Thomas Snow
When Icicle returns to enact the next phase of his devious plan, Caitlin and her mother, Dr. Carla Tannhauser, must resolve their long-combative relationship to defeat the icy monster. After Barry makes a big decision about their family without consulting her, Iris decides to take matters into her own hands.
- This episode title refers to the Snow family, whom Icicle planned to convert into ice personas permanently.
- When Iris and Ralph are preparing to use the time sphere to travel to the future, Iris asks Ralph if he's ready; Ralph then responds "All set to hit eighty-eight miles an hour". This is a reference to the Back to the Future franchise, and the fact that the DeLorean time machine used in the series needs to reach a speed of eighty-eight miles an hour to travel through time.
- This is the fourth episode of this season (and the series) not to feature Carlos Valdes (Cisco Ramon).
- The way Nora arrives in 2019 after exiting the Negative Speed Force is very similar to how the time remnant of Eobard Thawne/Reverse-Flash arrived in 2016 for the first time in "".
- The manner in which Thomas dies by sacrificing himself to save his daughter from Cicada is similar to how Quentin Lance died protecting Laurel, from Ricardo Diaz in Arrow's "".
- Near the end, the way Future Grace is watching over her unconscious younger self, is similar to the ending of "", when she watches over her unconscious uncle Orlin.
- The way Cicada killed Thomas was similar to how she killed her uncle Orlin in "".
- Thawne talking about his Negative Speed Force to Nora echoes how he spoke of the Speed Force during "" but negatively.
- In the West house, a box of pizza is shown with the logo, "Milgrom and McFarlane", a reference to Todd McFarlane who created Spawn and also worked on a lot of Marvel and DC titles and popularized Venom, and Al Milgrom was one of the creators of Firestorm with Gerry Conway.
- In 2049, on the back of the prison guard's magazine is an advertisement for Ralph's favorite soda gingold.
- Ralph refers to Eobard as "He who must not be named", a reference to Lord Voldemort from Harry Potter.
- The Negative Speed Force is actually pulling from Geoff Johns 2009 Flash Rebirth when Professor Zoom created the Negative Speed Force.
- The prison guard refers to Eobard as, "Hannibal Speedster," a reference to the fictional serial killer and cannibal, Hannibal Lecter.
- In the Flash 'Force Quest' storyline, besides the Negative Speed Force, there was also, the Sage Force, the Strength Force and the Still Force.
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