Futurama Episodes

Bender becomes envious of all the attention that Nibbler has been receiving. The annoyance culminates when Nibbler devours Bender’s homemade cake before he can gloriously unveil it. To get rid of the pest once and for all, Bender carelessly flushes Nibbler down the toilet. Leela is heartbroken and rightfully accuses Bender of lacking remorse. However, the Professor has a way to make Bender experience human emotion. He installs an empathy chip and sets it to Leela’s emotional frequency so that Bender can understand her loss. Motivated by misery, Bender heads to the sewers to bring back the missing pet and to put an end to his new-found regret, unaware of the dangerous mutants that inhabit the underground.
wikipedia.org summary:
During Nibbler’s birthday party, Bender becomes annoyed at how little attention he is getting and flushes Nibbler down the toilet. Distraught, Leela wishes that Bender could understand human emotions, so Professor Farnsworth installs an empathy chip in Bender so that he can feel Leela’s emotions as she feels them. Leela’s sadness of losing Nibbler becomes too great for Bender, who flushes himself down the toilet to find and rescue Nibbler in the sewers. Fry and Leela follow Bender and encounter a group of sewer mutants who live in fear of a monster called El Chupanibre, believing it to be Nibbler. Nibbler returns safely, but it turns out that he is not the monster, which appears alongside him. Bender tries to fight El Chupanibre, but Leela’s fear for Nibbler’s safety immobilizes him, so he convinces her to think only about herself rather than others, which gives Bender the strength to drive off the monster. Bender’s empathy chip is later removed, though he has learned nothing.
imdb.com summary:
When Bender flushes Leela’s pet, Prof. Farnsworth affixes an emotional transponder so he can feel what Leela is feeling. Trying to make Leela feel better so he can feel better, Bender, Fry and Leela descend into the bowels of New New York to find her pet.
tv.com summary:
After flushing Nibbler down the toilet, Bender gets an empathy chip installed in his head by the professor to make him feel what Leela is feeling after losing her beloved pet.