Where No Fan Has Gone Before - S4-E12
Easter egg: After choosing the episode "Where No Fan Has Gone Before", go down to home at the bottom of the screen and press right. The picture of the Star Trek cast and Futurama gang will change to a picture of the Planet Express ship with the engines from the enterprise attached. Press enter and you will hear David Goodman explain about guest voices on the show.
Easter egg: On the 4th season DVD, when it's on the episode selection on the 4th disk, scroll down to "The Devil's Hands Are Idle Playthings". Push left and it highlights an egg salad sandwich in the fridge, written in alienese. When translated, it says "This DVD includes a specially encoded Easter Egg which you are now meticulously translating from an alien language because you have no life and are a compulsive Nerdlinger(sic). How sad. Its especially sad if you don't speak English and you have to translate the alien language into English and then into your own tongue and you come upon a word like Nerdlinger, which really isn't a word at all, but still aptly describes someone who would actually translate such a word. Twice. And those of you who are reading this translation in a Futurama newsgroup aren't any better. We lurk on those newsgroups and we know what Nerdlingers you guys are, too. Of course you're also our biggest fans, which is sad in its own way. But, since you went to all this trouble to translate an Easter Egg, we do owe you something, so here's a secret about the show. The writers, producers, directors and most of the actors who worked on this show are all Nerdlingers, too."
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]