Long live the King.
The metahuman cure is finally completed and Team Flash decides that King Shark would be the ideal subject to test it on. But then Gorilla Grodd comes back to Central City and he and King Shark duke it out with each other.
- Always a Bigger Fish: No pun intended, but King Shark was expected to be this to Grodd by Team Flash. The height difference alone between the two is pretty noticeable. However, the actual fight was relatively even, and Grodd even knocks out King Shark, requiring Barry and Nora to intervene.
- Amplifier Artifact: Grodd uses the telepathic crown to enhance his powers enough to take over everyone in Central City. Even after it's removed it jump started his abilities into evolving all on their own, necessitating greater measures to contain him.
- Antagonist Title: The latter half of the Versus Title is the Monster of the Week.
- Arbitrary Skepticism: Averted. Lyla readily accepts that Nora is from the future. She points out that it's no weirder than finding out that her son used to be her daughter in an alternate timeline.
- Armor-Piercing Question: Cisco asks Barry if giving King Shark the cure was an impulse call or if it was always part of his plan.
- The Atoner: Shay Lamden takes full responsibility for his crimes as King Shark, even if he can't remember them. He makes the choice to turn back into King Shark since he's the only one immune to Grodd's mind control powers, even though this time it means the cure can't be used on him again.
- Badass Boast: Before fighting Grodd, King Shark lets out this gem:"King Shark wants you gone!"
- Battle in the Rain: It's fairly faint, but it is raining during the titular fight scene.
- The Big Damn Kiss: One between human Shay and Tanya after a lot of Unresolved Sexual Tension.
- Bittersweet Ending: The cure works and King Shark is no longer a villain, but he had to change back into a monster to stop Grodd.
- Bloodier and Gorier: The titular battle with Shark and Grodd is surprisingly bloody for this show with the two sustaining noticeable wounds as the fight drags on and culminating with Grodd's face being left a bloody mess. Considering the fact that the two are giant CGI animals this may be how the CW was able to get away with such violence on this show.
- Body Horror: Shay's transformation back from King Shark is shown to be both painful and fairly slow. Making matters worse, his body later starts reverting back to King Shark, but not all at once; his arm suddenly swells back to King Shark's size before it returns to normal.
- Brainwashed and Crazy: Cisco and Caitlin, courtesy of Gorilla Grodd's powers.
- The Bus Came Back:
- Grodd having not been in Central City since "Attack on Central City" because he was transferred to "Legends" for the 2017-2018 season where he was last seen in early 1990's Zambesi in "Guest Starring John Noble".
- King Shark was last seen in a cameo during the beginning montage of Crisis on Earth-X.
- Joe West finally comes back after a ten episode absence that began with "All Doll'd Up' due to his actor's medical leave because of back problems. In-universe, he's been to Tibet visiting Wally.
- Tanya Lamden returns after last appearing in "King Shark".
- Call-Back: The first thing King Shark said to the Flash was "Zoom wants you dead!". Here, the first thing he says to Grodd is "King Shark wants you gone!", showing his growth from one of Zoom's attack dogs to a heroic figure in his own right.
- Car Cushion: Grodd lands on a car after being shot off a crane via lightning throw.
- Catch and Return: Attempted by King Shark when he threw the cart thrown at him by Grodd back at the gorilla, but he missed.
- Combat Pragmatist: Grodd is not shy to use everything around him as a weapon against his opponent, when it becomes clear that King Shark physically stronger than him.
- Character Development: It's subtle and not discussed, but Lyla has gone from using King Shark as a glorified guard dog to actually trying to help and cure him like she said she would back in Season Two.
- Combined Energy Attack: Barry and Nora throw out a combined lightning strike to reanimate King Shark during the fight and also temporarily knock Grodd off his game.
- Continuity Nod:
- When Lyla gets introduced to Barry's Kid from the Future Nora, she doesn't pass it off as weird, since Barry did unwittingly replace her daughter with a son through time travel.
- The Enlightenment was the reason Grodd was able to escape ARGUS custody. During the Big Blackout the power dampener in his cell shuts down allowing him to briefly mind-control a guard and set up his Long Game.
- Barry once again uses his Supersonic Punch against Grodd. And by now, he is strong enough to actually make him feel it.
- Joe apparently remembers "Grodd hates bananas" and sent it to Iris like a meme.
- Convenient Coma: Lyla has Caitlin put Grodd into a comatose state to ensure he won't escape again.
- Cool Versus Awesome: The very point of this episode.
- Crossover: Since King Shark is in ARGUS custody, Lyla makes an obligatory appearance.
- David Versus Goliath: Grodd of all people is the David to King Shark's Goliath. Grodd is big, but compared to King Shark he is downright puny. As expected King Shark is the physically stronger one, but Grodd's intellect nearly allowing him to win before Barry and Nora intervene.
- Dead Guy on Display: While not dead, the way Grodd suspends King Shark over a crane is clearly intended to invoke this.
- Doppelgänger Replacement Love Interest: King Shark gets tons of Ship Tease with the widow of his late Earth-1 counterpart with the two kissing when Shay becomes a human again. Ultimately the two decide to keep their relationship going even after Shay reverts back to being King Shark again.
- Enhanced Punch/Elemental Punch: King Shark focuses the energy of the Speed force lightning Barry and Nora hit him with into his punch, allowing him to defeat Grodd.
- "Eureka!" Moment:
- When Caitlin suggests calling Harry for a meta volunteer from Earth-2, Barry realizes that they don't have to call Harry, since there's still an Eath-2 meta on Earth-1: King Shark.
- Joe realizes that Cicada must have at least one other accomplice since he keeps evading capture.
- Event Title: The episode revolves around Grodd and King Shark having to duke it out.
- Evil Plan: Grodd's plan is to use Dr. Lamden's telepathy crown to amplify his powers so he can control all of Central City.
- Face Plant: King Shark uses this as a finishing move on Grodd after the aforementioned Enhanced Punch.
- Foregone Conclusion: It's obvious that Shay won't be permanently cured, due to him fighting Grodd back in his mutated form in 12 hours.
- Future Imperfect: The Flash Museum states that a speedster is immune to mind-control. Nora is very annoyed that this is yet another fact the museum got wrong.
- Godzilla Threshold: Shay volunteers to transform back into King Shark and fight Grodd, even when told that he might not be able to turn back.
- Heel–Face Turn: King Shark is no longer a villain.
- Heroic Sacrifice: Shay gives up his chance of being human by turning back into King Shark permanently since King Shark is the only one immune to Grodd's mind control because of the animal part of his brain.
- Heroic Second Wind: After getting knocked out by Grodd, King Shark gets shocked back to consciousness by Flash and XS.
- Hoist Hero over Head: Grodd does this to King Shark after knocking him out.
- Hope Spot: Shay seems to be cured...until the remaining dark matter in his pituitary gland starts replicating and his body starts fighting back.
- How We Got Here: The episode starts with the Flash and XS laying on the ground with mind control helmets on their heads while Grodd and King Shark charge at each other. Then we flashback to twelve hours earlier and see the events that lead up to this moment.
- Hulk Speak: Averted. King Shark's speech has developed quite considerably since last year thanks to Dr. Lamden's efforts.
- Hypocrite: Cisco and Caitlin give Barry a What the Hell, Hero? speech about forcing King Shark to receive the cure without his consent, even if it's to save Cisco from getting eaten. While they're not wrong to be angry that he broke their agreement, this is the same cure that they're planning to use on Cicada, who is unlikely to consent to being cured under the current circumstances. And all of Team Flash has agreed to that plan, so Cisco and Caitlin don't have room to talk.
- Additionally, Barry only did it to save Cisco's life, something which Cisco doesn't seem to notice.
- Intrepid Reporter: Subverted. Iris was pretty bold in her decision to directly investigate Cicada in his civilian life but after learning he tracked down herself along with her friends and family and successfully killed them in multiple timelines she's very afraid to go work back at her office.
- Just Friends: What Tanya insists Shay is to her towards Sherloque. He obviously doesn't buy it.
- "King Kong" Climb: Lampshaded and discussed by Cisco who wonders why Grodd prefers that specific building: it is at the city's epicenter, from which Grodd can easily broadcast his mind control over the entire city.
- Leaning on the Fourth Wall: Joe tells Iris that he didn't just go to Tibet to visit Wally, but also for healing, obviously alluding to Jesse L. Martin's real life injury that kept the character off the series for so long.
- Locked Out of the Loop: Since Iris sat out the A-plot of the episode, she only learns about the eponymous brawl at the last moment, and laments the fact that she missed all of it.
- Look, a Distraction!: Grodd provokes King Shark into going on a rampage, so that he can escape ARGUS in the confusion.
- My Greatest Second Chance: Due to Tanya's own husband having died after mutating, she sees helping Earth-2 Shay as this.
- Mythology Gag: Grodd finally gets his trademark mind control helmet from the comics. He stole it from Dr. Lamden who developed it to help King Shark.
- New Powers as the Plot Demands: Once again, King Shark. Like his Healing Factor before, out of nowhere King Shark now shows the ability to absorb electricity and use it to power up his punches.
- No-Sell:
- King Shark's animalistic brain allows him to resist Grodd's mind control.
- Grodd's psychic abilities prevent satellites from detecting him. Somehow.
- Averted with Barry and Nora; despite what she heard in the Flash Museum, being a speedster does not provide immunity to mind control.
- Not Quite Back to Normal: Shay is returned to human form but, because the cure is only being tested, it doesn't completely purge the dark matter from his system, making a relapse a potential risk. His arm ends up transforming temporarily as they're examining him.
- Oh, Crap!: Barry when he sees Grodd in S.T.A.R. Labs using his powers to control Caitlin and Cisco.
- One Head Taller: Dan Payne (Shay) is noticeably taller than Zibby Allen (Tanya), most evident in scenes which have them standing next to each other
. - Power Glows: When King Shark channels the energy from the lightning throw to enhance his attack, his chest glows then his fist.
- Punched Across the Room: Despite their considerable bulk and height, due to their Super-Strength, Grodd and King Shark do this to each other. Barry's supersonic punch does it to even greater effect.
- Secondary Character Title: The former half of the Versus Title is a reformed recurring antagonist.
- Shipper on Deck: Sherloque encourages Tanya to get together with Shay, even after he is permanently transformed back to King Shark.
- Shout-Out: The GIF that is texted in the Dénouement is taken from an episode of The Simpsons.
- Smug Smiler/Slasher Smile: Grodd has this while boasting from the top of a tower that the people will now know only his will.
- Strong and Skilled/Unskilled, but Strong: Grodd and King Shark respectively. So it's no wonder that Grodd gets the upper hand, forcing the team to intervene.
- Talking Is a Free Action: Averted awesomely. After defeating King Shark, Grodd climbs up onto a crane and boasts about how he is going to rule the world, only to be shot off of it by a combined lightning strike from Barry and Nora.
- Tap on the Head: How Grodd gets the better of King Shark.
- This Cannot Be!: Barry's reaction when he realizes Cisco and Caitlin are being controlled by Grodd.
- Three-Point Landing: King Shark makes a grand entrance twice complete with this, once when he jumps out of water to meet Team Flash and then while dropping in via breach to fight Grodd.
- Ungrateful Bastard: When Barry uses the meta cure to save Cisco's life, Cisco's only response is to complain about how Barry gave it to King Shark without the latter's consent. Never mind how he was a second away from getting his head chomped off.
- Versus Title: Between King Shark and Grodd.
- Villain Forgot to Level Grind: Once again, like several villains before him, Grodd learns the hard way Barry is far more powerful than before. In previous seasons Grodd was fast enough to nearly keep up with Barry and supersonic punches did at the best Scratch Damage or Knockback Slide. Now? Grodd is unable to do anything before Barry socks him with a supersonic punch right in the face, which sends Grodd flying and knocks him clean out. Had Barry not grabbed the Idiot Ball and took time talk to Nora before removing the telepathic crown, the episode might have ended right there.
- Villainous Valor: Grodd doesn't hesitate for a second to go toe-to-toe with the much bigger King Shark. Even at the end, where Grodd is clearly in much worse shape than his opponent, he goes down swinging, making one last punch at King Shark before being knocked out.
- We Need a Distraction: Grodd telepathically sets off King Shark to create a distraction for his escape
- Wham Shot: Shay Lamden the human emerging from the water, no longer a shark monster.
- What the Hell, Hero?: Cisco and Caitlin chew Barry out for giving the cure to King Shark against his will. Barry admits he was wrong at the end of the episode and apologizes to Caitlin and Cisco.
- Window Love: Tanya and the now permanently transformed Shay have one such moment during the end.
- You Are Better Than You Think You Are: Joe encourages his daughter throughout the episode to face her fears and act strong.
- You Have GOT to Be Kidding Me!: Iris on the titular fight."King Shark vs. Gorilla Grodd, are you kidding me? I missed that?"
