Leela and the Genestalk - S7-E22
Trivia: When Fry, Bender, and Leela come into Mom's control room, the background sounds of the Enterprise (TOS) can be heard. Also in this episode, while Fry and Bender climb up the side of the castle, Adam West and Burt Ward make a cameo appearance as genetic experiments. They popped out of the window as the celebrities did in the original Batman series.