- "King Shark versus Gorilla Grodd? Are you kidding me? I missed that?"
- —Iris West-Allen
When Gorilla Grodd attacks Central City, Barry and Team Flash find themselves teaming up with an unexpected ally to defeat him – King Shark. However, when they hit a snag, they bring in Dr. Tanya Lamden to try to reach the man behind the shark, Shay Lamden.
- An upcoming fight between King Shark and Grodd was first referenced by Nora West-Allen in "".
- This was also subtly foreshadowed in the Season 3 episode ""; after Grodd was defeated and mentioned to have been locked up at A.R.G.U.S., Caitlin stated that he can be thrown into the same cage as King Shark (who's also in A.R.G.U.S. custody) for all she cares, since any good in him is long gone. Cisco then stated that that was a fight he'd pay money to see.
- This episode marks the second appearance of Dr. Tanya Lamden (who last appeared in ""), and the returns of Joe West (who last appeared in ""), King Shark (who last appeared in ""), and Grodd (who last appeared in "" on , while his last Arrowverse appearance was "" on ).
- Tanya was recast for this episode; in "", she was portrayed by Haley Beauchamp, while here, she's portrayed by Zibby Allen.
- Joe tells Iris that he traveled to Tibet to "heal", making an inside joke since Jesse L. Martin took a leave of absence from the show to recover from a back injury that he had sustained.
- Nora assumes that, as speedsters, she and Barry should be immune to Grodd's telepathic powers (something she learned from the Flash Museum, which Team Flash informs her is not true). This may be a reference to the fact that Barry is immune to telepathy in the comics.
- Lyla readily accepts that Nora is from the future, pointing out that it's not weirder than finding out that her son used to be her daughter in an alternate timeline, something Lyla found out in "".
- Cisco likens King Shark's freaking out when Grodd tries to control the latter to the 1987 film Jaws: The Revenge.
- Shark Week, an annual week-long TV programming block which features shark-based programming, was mentioned. It also was referenced by Leonard Snart in "" (where King Shark also made an appearance).
- After Cisco and Caitlin are verified to no longer be under Grodd's control, Cisco states "there are no more strings on us", referencing the 1940 film Pinocchio.
- Cisco refers to Grodd as the team's "simian Svengali", harking back to a character from the 1895 George du Maurier novel Trilby.
- Grodd falling from the construction crane and onto a car is a homage to the 1933 film King Kong, in which the titular gorilla, after getting shot by biplanes, falls to his death from the top of the Empire State Building.
- After the battle between King Shark and Grodd, Cisco states that it was the best "Kaijū" battle ever watched, a reference to the popular term used to refer to giant monster characters such as King Kong and Godzilla.
- Before they fight, King Shark says to Grodd, "King Shark wants you GONE!". That is similar to what he said to Barry in season 2 episode "" (where he told Barry, "Zoom wants you dead!").
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