Harley seeks a nemesis to raise her profile as a supervillain, but is disappointed when she gets stuck with Robin.
- Absentee Actor: Frank the plant is completely absent in the episode.
- Afraid of Blood: While this seems to be the case when King Shark says he can't handle blood at the idea of being the shark in their shark tank, it is later revealed that the sight of blood actually makes him go feral with Bloodlust and causes him to actually try to kill Robin when he nosebleeds into the tank. Doctor Psycho and Clayface admit that they both thought it was the former.
- Arson, Murder, and Jaywalking: Doctor Psycho dismisses Joker robbing a credit union because it's a "poor person's bank".Doctor Psycho: We robbed a real one with a vault, and money, and predatory lending practices!
- Big Damn Heroes: When Batman shows up to rescue Robin and starts fighting Harley, Ivy busts in to rescue Harley from him.
- Break the Haughty: Damian gets this when he inadvertently admits of lying about being Harley's nemesis in Tawny's show, and almost being killed by King Shark courtesy of his own nosebleed driving King Shark into a blood rage.
- Brick Joke:
- Lois suggests she and Superman go out for sushi after the kidnapping. Sure enough, they're watching Tawny's show in a sushi bar.
- When Harley tells Ivy she has a plan on how to get Robin to confess he lied about her being his nemesis, she starts off by saying "I've...", which Ivy misinterprets thinking she's saying a shorten version of her name "Ive". When Harley and Ivy has a Suggestive Collision moment on Tawny's show, they subtitled the moment saying "Kiss ya? Ive Harley even known ya!".
- Comically Missing the Point: Harley wants to be recognized for her crimes despite Ivy's continued insistence that the whole point of crime is not to be caught.
- Condescending Compassion: Superman treats Damian not unlike how a soccer mom would. Wiping his nose for him when he gets a nosebleed, phrasing his support as though Damian was nervous in facing his "nemesis" and generally embarrassing him.
- Does This Remind You of Anything?: Batman's talk with Robin about finding the right nemesis is framed exactly like The Talk. It's then spoofed when Robin flat-out asks Batman when he can have sex, and Batman ducks out of that conversation by claiming he can hear the Bat-Signal.
- Eco-Terrorist: Ivy insists on being called an eco-terrorist and takes a moment to berate the viewers for wasting water by rinsing recyclables.
- Engineered Public Confession: Harley tricks Robin into admitting he's a liar on Tawny's show by hiding the audience behind a curtain while she dangles him over a shark tank.
- Even Evil Has Standards: While Ivy thinks that Harley killing Robin is wrong for purely social reasons, the rest of Harley's crew thinks that killing a child is wrong for the same reason as everyone else.
- Everyone Has Standards: Played for Laughs. Both Harley and Superman agree that a $7.99 subscription to the Daily Planet is a bit much. It doesn't even include the crossword, which Superman thinks is ridiculous.
- Foe Romance Subtext: The whole episode frames the idea of arch-nemesis between superheroes and supervillains as being like celebrity romances.
- Heroes Gone Fishing: The fight on Tawny's show cuts to various heroes watching, such as Aquaman watching on his phone while on the toilet (underwater), Superman and Lois at the sushi restaurant, and Wonder Woman at home eating (her brand) of cereal.
- I Resemble That Remark!: Harley describes Doctor Psycho's nemesis as his inability to not use the c-word. Doctor Psycho insists his nemesis is Wonder Woman and nearly calls her the c-word, but catches himself and admits Harley has a point.
- Mêlée à Trois: When Joker shows up to fight Batman during Tawny's show, it becomes a free-for-all. Eventually, Joker grabs Robin and runs off so Batman will be forced to chase him.
- Mistaken for Pregnant: When Harley walks in on the prank Joker left for Harley at her and Ivy's apartment, Harley briefly thinks that this was Ivy telling her that she was pregnant.
- Mythology Gag: How does Batman incapacitate King Shark? With Shark-Repellent Bat Spray!
- No-Sell: When Harley mistakenly attacks King Shark with her trusty bat, breaking it on his face, his reaction is just a nonplussed "Ow?".
- Not So Different: In the end of the episode, Robin is this for Harley, unable to find a nemesis himself just like her.
- Not Worth Killing:
- Zig-zagged in regards to Harley and Robin. Harley doesn't feel Robin is worth her time, but the fact that everyone believes him to be her nemesis infuriates her to the point that she considers actually killing him. She's talked into a less-drastic course of action.
- Superman doesn't think Harley is worth fighting, so he brings Robin along to do it for him. Harley is so annoyed she just leaves on the spot.
- Pass the Popcorn: When Harley gets into a fight with Batman, and later Ivy and Joker joins in, Harley's crew just sits with the audience and watches the fight. Doctor Psycho is even eating popcorn.
- Poor Communication Kills: When King Shark tells the others that he's not good around blood, they assume he was fainty around it. But when Robin's blood gets in the water and he smells it, he goes on a rampage and tries to eat him.Doctor Psycho: Oh, you know what? This must be that "not being good with blood" thing. I thought it just meant he got a little fainty.
Clayface: I did, too.
Doctor Psycho: It was misleading.
Clayface: How funny.
- Pragmatic Villainy: When Harley suggests she could just kill Robin when she can't get rid of him, Ivy points out this would just validate him as her nemesis. King Shark adds that she would also be seen as a child killer, which would be even worse publicity.
- Racist Grandpa: Sy Borgman rants to Ivy about how he doesn't allow certain things in his building. Ivy cuts him off at "communists", feeling he was going in a racist direction. He later evicts her on the grounds that King Shark qualifies as a pet, which King Shark thinks is racist, or at the very least xenophobic.
- Shout-Out: King Shark's reaction to sniffing Robin's blood brings to mind Bruce from Finding Nemo, right down to the way the blood trails in the water and the way his irises enlarge.
- Skewed Priorities: Ivy takes a moment from fighting Batman to give the viewers a lesson on water conservation, giving Batman enough time to free himself from her vines.
- Strange Minds Think Alike: Harley complains about the $7.99 subscription to the Daily Planet before deciding to kidnap Lois Lane to make her retract a negative article. When Superman shows up to rescue Lois, he thinks it's about the subscription fee.
- Suggestive Collision: This happens between Harley and Ivy while they're fighting Batman. Whoever's doing the subtitles for Tawny's show even comes up with a pun on the fly:Subtitle: Kiss ya? Ive Harley even known ya!
- Villain Cred: Harley is trying to get a worthy nemesis so she'll be seen as a legitimate supervillain, and is annoyed that she's stuck with Robin. When she does finally get Batman's attention, Joker shows up, annoyed that she's stolen his nemesis.
- Villainous Rescue: Harley actually saves Robin from her own death trap when King Shark goes into a frenzy and poses genuine life-threatening danger.
- Visual Pun: Aquaman watches the battle between Harley and Batman on his toilet. In other words, he's sitting on his throne.
- Would Hurt a Child: After Joker sends a condescending message to Harley about her "rivalry" with Robin, Harley decides that she's going to kill Robin to make it stop. Ivy believes she is capable of doing it, but that doing so will only validate everyone's belief that Robin is her nemesis, while the rest of her crew thinks that she would just be crossing the line.
- Wrecked Weapon: Harley snaps her bat in half against King Shark when she mistakes him for an enemy. She's forced to make do with a pipe against Batman.