My Problem With Popplers (a.k.a. The Problem With Popplers) - S2-E18
Fry/Bender: Pop a Poppler in your mouth, When you come to Fishy Joe's, What they're made of is a mystery, Where they come from, no one knows. You can pick 'em, you can lick 'em, You can chew 'em, you can stick 'em, And if you promise not to sue us, You can shove one up your nose.
My Problem With Popplers (a.k.a. The Problem With Popplers) - S2-E18
Professor Farnsworth: Hey, unless this is a nude love-in, get off my property.
Hippie Protester: You can't own property, man.
Professor Farnsworth: I can, but that's because I'm not a penniless hippie.
Answer: You are thinking about episode 20 of series 2 - "Anthology of Interest I". She technically never kills anyone, but in the episode she ask a "What if machine" (one of the Professor's inventions) what would happen if she was more impulsive. The machine then shows the more impulsive Leela killing off the Professor to get the money from his will and thereafter killing Hermes, Bender, Scruffy, Cubert, Nibler, Amy and Zoidberg to cover it up. Finally she does something really impulsive with Fry.
Andreas[DK]