When Fry becomes infested with parasitic worms (after eating an egg salad sandwich from a truck-stop bathroom on another planet) that make him stronger and smarter, he finally finds the perfect way to profess his feelings to Leela. Meanwhile, the rest of the crew goes on a Fantastic Voyage-esque journey into Fry's body to eradicate the worms.
- Ass Shove:Zoidberg: We'll need to look inside you with this camera.
(Fry opens his mouth)
Zoidberg: Guess again. (Fry looks worried)
- When Fry decides to confront the worms he drops the robotic version of himself into the back of his underpants, implying the robot enters this way.
- Beneficial Disease: Eating a bad sandwich gives Fry worms that rebuild his body, making him stronger, smarter and irresistible to the woman of his dreams. However, Fry gets rid of them after he realizes Leela was only attracted to him because of the changes the worms have made.
- Bittersweet Ending: Fry's been rejected by Leela, and gone back to being the lazy, slovenly idiot he was... but he's determined to keep trying, and even manages to briefly get the holophoner working at the end.
- Body Horror: It's implied that this would have happened if the crew had succeeded in disturbing Fry's pelvic splanchnic ganglion, he would have crapped out practically his entire body, or at least his entire skeletal structure.
- Chekhov's Gun: That the worms fixed Fry's ability to produce sperm, while a one-off gag here, will become very important later on in the series.
- Continuity Nod:
- Amy comments on the state of Fry's rectum, probably (hopefully) having gotten a look back when they were dating.
- The suits used for controlling the mini-droids are the same the gang used to explore the internet in "A Bicyclops Built for Two".
- Zoidberg briefly rides on one of Fry's sperm, the worms having fixed it up after Bender sterilized Fry back in "Fry and the Slurm Factory".
- Cursed with Awesome: Most of the Planet Express crew acts as though the worms are these terrible parasites that infected Fry when all they do is improve his body, giving him regenerative healing, enhanced strength, and improved intelligence.
- Falling-in-Love Montage: Fry's performance on the holophoner for Leela looks very much like a Falling-In-Love Montage. They dance a Dance of Romance on a planet's ring, their faces appear kissing on the surface of the ocean, they swim together as seals, and end up dancing again in a pearl.
- The outfit that Leela falls asleep in while waiting for Fry to return to her apartment is very... revealing to say the least.
- Fry starts ripping off his own shirt and red jacket to reveal that he's gotten ripped. Leela makes a rather... appreciative sound.
- "Fantastic Voyage" Plot: The Planet Express team enter Fry's body to interact with the worms that started living there. In a twist, they don't shrink because, according to Professor Farnsworth, "That would require extremely tiny atoms" that he's not willing to pay for. Instead, the party uses miniature robot replicas of themselves. This gives Leela('s miniature) the opportunity to slice and dice them up without any long-term ramifications. It also allows for Fry to create his own tiny robot, thus effectively allowing him to go inside his own body.
- "Flowers for Algernon" Syndrome: After becoming smart and muscular thanks to the worms, Fry manages to attract Leela, but then starts to think that what Leela loves is not the true charmingly dimwitted Fry, but what the worms made him into. His fear is proven true when after getting rid of the worms, Leela rejects him. Hell, even before he got rid of the worms, Leela outright says she loves what he'd become.
- Flowers of Romance: New-and-improved Fry spontaneously buys flowers for Leela, whom he has loved almost since the moment they met.
- Genius Serum: Fry eats an egg salad sandwich containing worms which go on to improve his body, making him stronger and smarter. After a failed attempt by the Planet Express crew to exterminate them because of Leela, Fry chooses to get rid of them himself and return his body to normal in order to find out if Leela truly loved him or what the worms made him.
- Heroic Build: Fry becomes jacked after the worms start repairing his body.
- Heroic Host: Fry gets infected with worms. These worms make Fry stronger, smarter, and healthier. The Planet Express crew travel into Fry's body to get rid of the parasites, then Leela stops them because she likes the new Fry better. And then Fry removes the parasites anyway because he wants to know that Leela likes him and not what the parasites made him into.
- Hidden Depths: Only a few people in the universe can play the holophoner, and they're not very good at it. At the very end, Fry, who has little to no experience with one, manages to play it for himself.
- Hoist by Their Own Petard: The worms aimed to improve Fry's own physical body, which he uses against them and gets them to leave by force.
- I Take Offense to That Last One!: Fry tries defending Leela against the truck-stop men's insults. It doesn't really work.Sal: She don't gots enough meat for a guy like me.
Fry: She does too! She's loaded with meat! She's got more meat than a cow!
- Incredible Shrinking Man: Averted, in that Professor Farnsworth has the whole gang use motion-controlled miniature avatars (instead of just shrinking them) to go into Fry's unaware body. When asked why, Farnsworth explains that shrinking "would require very tiny atoms... and have you priced those lately? I'm not made of money. Leave me alone!"
- It Came from the Fridge: The blackened egg sandwich Fry eats from a dispenser at a truck stop bathroom.
- It Tastes Like Feet: When Fry eats a bad egg salad sandwich, he says "It's like there's a party in my mouth and everyone's throwing up!"
- Love Makes You Dumb: The worm leader asserts that Fry is bluffing about injuring himself because "no creature would willingly make an idiot out of itself." Fry retorts that the worm leader has never been in love.
- Mini-Me: The reason the Planet Express crew use miniature motion-control robots of themselves instead of simply just shrinking down to smaller size is because the latter would be too expensive, according to the Professor.
- Nausea Dissonance: The rest of the Planet Express crew's reactions towards watching Zoidberg's analysis on Fry and discovering there's more worms in his intestines.Hermes: It's nauseatin', mon! (eats a handful of popcorn)
- Not Helping Your Case:
- Fry's attempts to defend Leela from Sal and the other trucks in the beginning are nowhere near successful.
- After getting rid of the worms, Fry pleads for a chance to be romantic on his own. Leela's already dubious, but then Fry brings up that time he dated Amy, at which point Leela kicks him out.
- Pass the Popcorn: When Zoidberg investigates Fry's bowels with a surgical camera, everybody goes into a side-room with a video-screen and two-way mirror and... eats popcorn. Hermes eats his with a jai alai scoop.Hermes: It's nauseating, mon! [takes another handful of popcorn]
- Physical God: Fry was actually this to the worms.
- Puddle-Covering Chivalry: Fry does a more believable variation of this on his date, stepping into a puddle so he can help Leela cross it without getting her boots wet.
- Running Gag: Bender crying "Abandon ship!" whenever their submarine is jostled. Or remotely near danger.
- Saw It in a Movie Once:Zoidberg: We can escape through the nasal capillary into the sinus!
Hermes: Strange. Usually, you don't know anything about human anatomy.
Zoidberg: I learned it from a decongestant commercial. "Soothing action, action, action, action..."
- Shout-Out: The title of the episode is a Shout-Out to Paradise Lost.
- Smart Ball: Zoidberg finally gets something right about human anatomy. Hermes even points it out, though it turns out Zoidberg had learnt the information from a decongestant commercial. Seconds later he mixes up the heart and the stomach.
- Sword Fight: Fry and the Worm King engage in one.
- The Symbiote: The worms build a society in Fry's body, and in return give him Super Strength, a Healing Factor, and improved intelligence (among other things). Unfortunately, Fry has to get rid of them to prove whether Leela fell in love with him or the man the worms made him into.
- Take That!:
- Truck stop sandwiches are a source of worms.
- After Fry damages a few bits of his brain, the Worm King informs him that this is no worse than "a week of binge drinking or five minutes on a cell phone".
- Before leaving, the Worm King informs Fry "one day you'll be eating a fast-food burger and BOOM! You'll be crawling with us again! Ever wonder what makes special sauce so "special"? Yo."
- Tempting Fate:
- Fry purchases a sandwich from the truck-stop vending machine, and is asked whether this is a good idea.Fry: What's the worst thing that could happen? (beat) Ugh. It's like a party in my mouth, and everyone's throwing up!
- The Professor keeps doing this during the journey through Fry. Such as telling no one to make a smell. Fry then sniffs a rose, or hope nothing makes his heart beat faster. He and Leela touch hands.
- Fry purchases a sandwich from the truck-stop vending machine, and is asked whether this is a good idea.
- This Is Gonna Suck: Averted with Zoidberg.Farnsworth: Anyhoo, your net suits will let you experience Fry's worm-infested bowels as if you were actually wriggling through them.
Zoidberg: There's no part of that sentence I didn't like.
- Too Dumb to Live: Bender drinking ethanol while trying to light a cigar. The results are predictable.Bender: (his head flies across the truck stop after an explosion) Comin' through!
- Verbal Tic: Sal and his extra 's'. In this episodes it spreads to everys words he sayss.
- Yank the Dog's Chain: Fry finally manages to impress Leela and earn her affections... only to throw all away deliberately, thus causing Leela to kick him to the curb.