Zoidberg is acting very strange—murderously so, in fact. It transpires that it's time for his people to mate, so the Planet Express crew take him to Zoidberg's planet. But the doctor isn't a hit with the ladies, so Fry decides to help, which leads to other problems.
- Abhorrent Admirer: Edna ends up falling for Fry when she discovers that he was the one teaching Zoidberg to act more romantic. He couldn't be more horrified.
- An Arm and a Leg: Zoidberg cuts off Fry's arm while Fry is making a speech about how they're friends. And then Zoidberg cuts off the wrong one trying to fix it.
- Assurance Backfire: After Zoidberg's display fails to attract a mate, Leela tries to cheer him up by telling him he didn't smell as bad as the other Decopodian males.Zoidberg: You're right! My stink gland is weak!
- Be Careful What You Wish For: Fry gets excited at the prospect of "an orgy of invertebrate sex" at the Decapodian homeworld. Well, just the sex part. Until Edna is infatuated with him...
- Beware the Nice Ones: Fry is all mellow while he was fighting with Zoidberg to the death. But when Zoidberg cuts his arm off, he screams "You BASTARD!!! I'll kill you! YOU BASTARD!!!"
- Bittersweet Ending: Zoidberg fails to mate with Edna, and it's implied that he'll never have another opportunity to find a mate. However, if he had mated with Edna, Zoidberg would have died afterwards.
- Bloodless Carnage: Fry's severed arm does bleed very slightly when Zoidberg cuts it off, but nowhere near as much as it would in real life.
- Bowdlerization: On Channel 4 in the UK, the part where Fry gets his arm cut off after his speech about how he can't kill Zoidberg because of their friendship is cut to remove the shot of the dismembered arm on the ground and Fry yelling, "YOU BASTARD! I'LL KILL YOU!"
- Butt-Monkey: Bender sums Zoidberg up as "the lobster equivalent of Fry!" He might be right.
- A Date with Rosie Palms: Implied.Zoidberg: The frenzy is over. How will I ever get rid of my male jelly now?Fry: I'll lend you this. (offers Zoidberg his severed arm)Leela: Fry!
- Death by Sex: All Decapodians. Fry sums it up.Fry: You mean you have to choose between a life without sex or a gruesome death? Tough call.
- The Dog Bites Back: Zoidberg kills and eats his old school bully.Zoidberg: Whos the tough guy now, Vinnie?
- Duel to the Death: Zoidberg challenges Fry to Claw-Plagh after catching him with Edna.
- Eloquent in My Native Tongue: When one of Zoidberg's friends said his name as a pattern of squawks and clicks, Fry wondered if that was Decapodian speech for Zoidberg, causing Zoidberg's friend to run off, crying.Zoidberg: You didn't have to call attention to his speech impediment.
- Face Death with Dignity: Subverted completely by Fry, who tries running for his life when the odds turn against him.Leela: Come on, Fry! Die with dignity!
- Failed Attempt at Drama: Fry gives a stirring speech about his and Zoidberg's friendship and how he refuses to fight his friend. Said friend wasn't paying attention; Zoidberg cuts off Fry's arm while he's distracted, provoking Fry into a violent rage.
- Fanservice: Fry accidentally going into the women's steam room, where Leela and Amy are relaxing naked. Amy moves the hand covering her chest, but just enough to keep it still covered (according to the DVD commentary, the writers used this scene as a bargaining chip for the FOX censors when they wanted to get away with something that the censors would immediately decline, telling them "You let us get away with this. Why can't you do the same with this scene?").Fry: Coed steam rooms? I love the future!Leela: Fry, you're in the women's steam room.Fry: Futuristic.Amy (aside to Leela): Psst! Look what life was like before genetic engineering.Leela: Those poor 20th-century women.(Fry swings his legs closed)
- Foreshadowing: The Decapod King said that he would embrace a life of celibacy to uphold Decapod's crazy traditions (namely Claw-Plach). This should've been a hint that Decapodians die after mating.
- Gladiator Games: Claw-Plach. A fight to the death over matters of honor (and also whether or not abbreviations count in Scrabble. "They don't!").
- Gone Horribly Right: Fry tries to get Zoidberg together with Edna by teaching them both about love, a concept unknown in Decapodian culture. Unfortunately, Edna instead ends up becoming attracted to Fry, and Zoidberg in turn becomes insanely jealous and challenges Fry to a Claw-Plach battle to the death.
- Grievous Harm with a Body: Fry starts beating Zoidberg with his recently severed arm.
- Groin Attack: Subverted. Zoidberg says he'll claw Fry in the gonads, while pointing at his neck. Fry urges that nobody correct him.
- Homage: Fry Plays Cyrano for Dr. Zoidberg. Of course here Fry is not so fortunate when the lady decides that she wants him instead she's a hideous Starfish Alien so the plot shifts gears and we're suddenly watching "Amok Time".
- How Is That Even Possible?:Amy: Bender, your beer belly is so big your door won't close. And that doesn't even make sense.
- I Take Offense to That Last One!:Leela: No offense, Fry, but you've become a fat sack of crap.
- I'll Kill You!: Fry to Zoidberg after Zoidberg cuts off one of his arms.Fry: You Bastard!! I'LL KILL YOU! YOU BASTARD!
- Inherently Attractive Profession: Zoidberg has his eye on a Decapodian named Edna, but she's not interested. Leela tries to convince her by telling her that "he's a doctor. A doctor, honey!"
- Insult Backfire: A Running Gag:Fry: Start with a compliment. Tell her she looks thin.
Dr. Zoidberg: You seem malnourished. Are you suffering from internal parasites?
Edna: (pleased) Why, yes. Thanks for noticing.
Edna: Teach me to love, you squishy poet from beyond the stars.
Fry: (horrified) I'm flattered, really. If I was gonna do it with a big freaky mud bug, you'd be way up the list.
Edna: (aroused) Hush, you romantic fool. Engage your mandibles and kiss me.
- Is There a Doctor in the House?: Said by a gym instructor when Zoidberg's rampage causes several pregnant women to break their water.Zoidberg: (Gonk face) I'm a doctor!(More women give birth)
- It's All About Me: Bender, as per usual.Bender: Fry, I've never asked you for anything before but, if it's not too much trouble, when it comes to the ninth round just let him win.Fry: But it's a fight to the death!Bender: Oh, so this is suddenly all about you?!
- Major Injury Underreaction: Downplayed. Fry is pissed when Zoidberg cuts off his arm, but doesn't seem in pain.
- Maternity Crisis: Triggered en masse when a hormone-addled Zoidberg interrupts a prenatal aquarobics class.
- Mood Whiplash: Fry is in the middle of a moving speech about The Power of Friendship when Zoidberg cuts off his arm and an enraged Fry starts trying to beat him to death with it.
- Morton's Fork:Dr. Zoidberg: (murderously angry) Fry. I challenge you to clawplach.
Fry: English, please?
Dr. Zoidberg: A fight to the death.
Edna: And if you survive, we'll make sweet love.
Fry: (beat, then screams)
- Nice Job Breaking It, Hero!: Leela telling Edna that all of the things Zoidberg had been saying to her were put in his head by Fry is what leads to Edna becoming infatuated with Fry and Fry and Zoidberg having a duel.
- Non-Mammal Mammaries: The Decapodian women have breasts, but lay eggs and do not take care of their young. Edna is even the page image.
- Normal Fish in a Tiny Pond: Fry's girl-wooing tactics are pretty amateur-hour stuff, consisting of things like "compliment the girl regularly," "pretend to listen when she's talking," and "don't ask for sex until at least the third date." But to a member of a species with no concept of love for any reason besides mating, he's The Casanova.
- Not What It Looks Like: This happens to Fry, when Edna comes on to him as Zoidberg stops by her apartment. Unfortunately, Edna claims it is.
- Off with His Head!: At the very end of the episode, this happens to Fry due to Zoidberg's... "help".
- The One That Got Away: Fry's demonstration while giving love advice to Zoidberg causes Leela to recall her ex-boyfriend and subsequently run away crying.Fry: [takes Leela's hand] All you have to do is look her in the eyes and say [faking tears of joy] I've never been so happy.Leela: [scoff]s Ugh, if a guy did that, I'd know it... wait a minute, they've all been saying that! Even Sean! [She runs off crying.]
- Out with a Bang: Turns out Decapodians only mate once, then die.
- Playing Cyrano: Fry, for Zoidberg, courtesy of a conveniently placed clamshell.
- The Power of Friendship: Subverted. Fry gives a speech about how his and Zoidberg's friendship won't be torn apart over a woman... only to have his arm cut off by Zoidberg mid-speech. Fry promptly gives up and starts whacking Zoidberg with the severed limb. The fight only stops when Leela points out that the spectators are all gone and Zoidberg realises that he's missed the mating frenzy.
- Rule of Funny: The plot gets kicked off by the crew deciding to sign up for the gym. Leela and Amy walk into the Planet Express lounge, where a noticeably-chubby Fry and Bender are watching TV.
- Shout-Out: The Decapodian national anthem is the fight music from the Star Trek: The Original Series episode "Amok Time". Fry reacts accordingly.Fry: Uh-oh.
- The title is one to Dion and the Belmonts' song "Why Must I Be a Teenager In Love".
- Skewed Priorities: When a member of Zoidberg's species has sex they die immediately afterward. When Fry learns that Zoidberg has to choose between a life without sex or a gruesome death, he says, "Tough call."
- Squick: In-universe example. Fry, Leela, and Bender are grossed out by the green bubbling ooze that resulted from the Frenzy.
- Too Dumb to Live: Amy, who keeps removing the rubber bands binding his claws. Even after he's clawed her up, she still doesn't learn and keeps falling for his claims that he's not crazy anymore.Bender: Moron.
- Ungrateful Bastard: Fry actually manages to get the upper hand against Zoidberg and could have killed him if he'd so desired, but refuses and attempts to make a Patrick Stewart Speech about Zoidberg being his friend. Zoidberg responds by cutting one of Fry's arms off. A now-pissed off Fry decides he's okay with killing Zoidberg after all.
- What Is This Thing You Call "Love"?: Zoidberg is only looking for someone to have eggs with, so he's a bit confused about these new emotions.Zoidberg: This "love" intrigues me. Teach me to fake it.
- Some time later:Zoidberg: I'm confused, Fry. I'm feeling a strange new emotion. Is it love when you care about a female for reasons beyond mating?
Fry: Nope. Must be some weird alien emotion.
- Some time later:
- Who's Laughing Now?: On returning home, Zoidberg finds his old childhood bully (a hermit crab), and eats him.Zoidberg: Who's the tough guy now, Vinny?!