Becoming His Own Grandfather
"For example, if you killed your grandfather, you'd cease to exist!"
―Farnsworth
"But existing is basically all I do!"
―Fry[src]
The Planet Express crew had gone to observe a supernova up close. While the crew prepared for the event, Fry went to make popcorn. He ignores the warning label on the aluminum popcorn pan, stating not to cook in a microwave, which he does. The microwave emitted radiation that collided with the wave from the supernova, causing the Planet Express crew to travel back in time to 1947. After Bender breaks apart, Zoidberg was captured by the U.S. military while picking pieces of his torso. Fry and Bender's head attempt to infiltrate Roswell, with the former disguised as a soldier. He runs into his grandfather, Enos Fry, engaged to Mildred. Acting on Farnworth's warning, Fry did his best to make sure that his grandfather is not killed, otherwise he in turn would cease to exist. However, he became paranoid in his attempts to protect Enos, driving and locking him in a house in the middle of nowhere. But what he didn't know was that he left Enos within range of a nuclear testing ground, killing him in the resulting explosion. But for some reason, Fry was still existing. He comforts his grandmother, who begins to make sexual advances on him, which made him uncomfortable. He then reasoned with himself that because he still exists, Mildred can't be his grandmother and sleeps with her. Next day, Farnsworth knocks on the window, informing Fry that because of his actions, he himself became his own grandfather; Fry freaked out. Because of the paradox, the Planet Express crew decided that they should get back to their own time, regardless of what it would cause to history. They storm Roswell, rescuing Zoidberg during an autopsy, Bender's reconstructed body and stealing a microwave satellite dish to return to the future.
It is later explained by the Nibblonians that because of Fry becoming his own grandfather, it caused a genetic abnormality that caused him to lack the delta brainwave, which rendered him immune to the Brainspawn and telepathy in general.
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