That Darn Katz!.Amy applies for her doctorate in applied physics by presenting a thesis for harnessing the power of Earth's rotation, but is interrupted due to her allergy to the committee chairman Professor Katz's cat and rejected. The cat follows the Planet Express crew home and summons a group of other cats in a flying saucer to brainwash the rest of the crew except for Amy and Nibbler, who discover Katz's cat to be the chairman's true identity and all cats to be a hyper-intelligent alien race from Thuban 9, a planet that lost its rotation and led to extreme temperatures on both eastern and western hemispheres. Katz uses Amy's thesis to build a machine powered by the brainwashed crew that transfers Earth's rotational energy to Thuban 9. Free from the cats' control, the crew is unable to reverse the process when Amy suddenly realizes they can instead continue it until they restore the planet's rotation, albeit in the opposite direction. The plan is successful, once again halting the rotation of Thuban 9, and Amy receives her doctorate for her efforts.