"Why Must I Be a Crustacean in Love?" is the fifth episode in second production season of Futurama. It originally aired on the Fox network in the United States as the ninth episode of the second broadcast season on February 6, 2000. The episode is a parody of the Star Trek: The Original Series episode "Amok Time" and, in part, Cyrano de Bergerac.

Amy and Leela drag Fry and Bender to the gym, and Doctor Zoidberg tags along. While at the gym, Zoidberg behaves erratically and aggressively, and even develops a head fin. Back at the laboratory, Professor Farnsworth examines a restrained Zoidberg, and determines that it is mating season for Zoidberg's species.

The crew flies to Zoidberg's home planet, Decapod 10, and, after a short tour, Zoidberg sets up a mound on the beach and begins trying to attract a mate. After an unsuccessful day, Zoidberg meets Edna, an old classmate, who rejects him and leaves him very depressed.

Fry begins teaching Zoidberg how to win Edna's heart using human romance techniques. Zoidberg struggles to understand how this could work but he eventually gets the idea, and, using his new-found techniques, successfully woos Edna to a date. While at a restaurant, Leela reveals to Edna that Fry is responsible for the change in Zoidberg. Under the pretext of discussing Zoidberg, Edna invites Fry to her apartment and begins an unsuccessful attempt at seducing him. Zoidberg walks in, sees them 'embracing', and challenges Fry to Claw-Plach, a ritual fight to the death.

In the Claw-Plach arena, Fry is about to defeat Zoidberg, but cannot kill his friend. Unfortunately, Zoidberg does not feel the same way and cuts Fry's arm off with his claw, prompting an astounded Fry to shriek "You bastard, I'll kill you! You bastard!", before proceeding to beat Zoidberg with his severed arm. After more fighting, Fry and Zoidberg look up to discover the entire Decapodian audience has left – including Edna, who has decided to mate with the king. Once every Decapodian is underwater, masses of eggs float to the surface; Zoidberg has missed the mating frenzy of his species. They soon witness the corpses of all the Decapodians float to the surface, where they are feasted on by seagulls. Zoidberg explains that members of his species die after mating and apologizes to Fry about how he acted. He felt things he never felt before: "love, jealousy, passion for disemboweling". He then tries to reattach Fry's arm, but instead he reattaches it on the wrong side, and when trying to fix that he ends up cutting off Fry's legs. Followed by that second mistake, the scene pans out to the ship with an audible squish sound as Zoidberg ends up removing another unknown body part.

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