Gravity Groove is the 16th episode of Season 1. It first aired on May 29, 2009.
Lisa & Shock plan to enter a dance-off. Unfortunately, Francine, who is also a contestant , sabotages Shock by using Skeleckian Gravity Spray, which makes Shock's legs heavier. Hector convinces Lisa not to give up, but Francine also sprays Lisa, making her legs heavy. Now the two of them must solve this problem.
•Saturday Night Live cast member Bobby Moynihan guest stars as the Skeleckian Gravity Spray spokesperson.