Continuity mistake: Season 6, episode 19 "Yo Leela Leela": When Bender discovers Leela's secret writing place, throughout the entire scene the lipstick marks on his head keep changing places, sometimes disappearing and reappearing. Most noticeable is the one on the right side of his head: it disappears when he is shown from that side, then reappears as soon as the angle changes.
Continuity mistake: When everyone is being scanned by the machine that determines who stays on Earth and who gets evacuated, the machine approves Amy, saying that they were in the same sorority and they do a "Sigma Beta" dance. In the first episode, Amy says that her sorority is Kappa Kappa Wong. (00:10:30)
Zapp Dingbat - S7-E5
Continuity mistake: When Turanga Munda walks down the aisle to marry Zapp Brannigan one of her tentacles changes color for a brief period. (00:16:00)
Continuity mistake: Early in the swim to the ocean, salmon Scruffy is eaten by Zoidberg. Later, during the the swim back to the stream, Scruffy is seen with the group, just behind Leela and Fry.
Saturday Morning Fun Pit - S7-E19
Continuity mistake: The five arrive at the theater. When Fry says "Search me, no don't. I'm carrying", there is no-one next to Fry on the left for a good foot and a half. In the next shot, Amy has appeared about a half foot next to him. (00:02:25)
Saturday Morning Fun Pit - S7-E19
Continuity mistake: When the first Larry Bird clone is created, he is standing next to the cloning machine. When the rest of the clones are made, the first clone is no longer there. (00:05:15)
Saturday Morning Fun Pit - S7-E19
Continuity mistake: When the first Larry Bird clone finishes his line, one of his arms is raised. The next shot shows both arms are by his side. (00:05:15)
Saturday Morning Fun Pit - S7-E19
Continuity mistake: Hermes begins to tie the thing around his neck. One half of the cloth is around his neck whilst the other half is on his shirt collar. He ties it and the half of the cloth around his shirt collar has gone to his neck despite never touching it. (00:06:35)
Saturday Morning Fun Pit - S7-E19
Continuity mistake: Both times the Globetrotter turns the cloning machine on, after the shot goes to a wide view, the knob is pointed to the OFF position, but the machine works anyway.
Leela and the Genestalk - S7-E22
Continuity mistake: When Leela's parents call Fry on her "wrist thingie", we see it has clamps on the back that go like "up down up down" but in the middle of the sequence they change to "up down down up". (00:12:50)
Stench and Stenchibility - S7-E25
Continuity mistake: As Bender sits down in the audience, he's putting duct tape on his leg to repair it. As he tap dances on the dead girl, it's suddenly complete with no tape.
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]