Easter egg: When you choose "When Aliens Attack" go to special features and press on his remote, it will take you to a hidden poster.
My Problem With Popplers (a.k.a. The Problem With Popplers) - S2-E18
Easter egg: Highlight "Play Episode" and press up to highlight the Poppler. Press "Ok" to enter a "The Class of Futurama" poster.
Easter egg: On the sub menu click up highlighting nibblers eyeball and then press enter.
Easter egg: Click left on the sub menu while highlighting the tiara and then press enter.
How Hermes Requisitioned His Groove Back - S2-E14
Easter egg: Click right three times to highlight a floppy disc on the sub menu and then press enter.
A Bicyclops Built for Two - S2-E13
Easter egg: Click left on the submenu highlighting jewel and then press enter.
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]