The Big Bang Theory
Stewie goes back in time to mess around with Brian. Eventually, Brian catches him inside the time machine. In fighting over its controls, they are accidentally transported out of the space-time continuum, where the laws of physics do not apply and where the return pad cannot get them home. Stewie decides to take a risky effort to overload his return pad to bounce them back into the space-time continuum. Stewie later determines that he was the cause of the Big Bang, because the background radiation that created the universe matches the signature of his return pad.While getting plutonium to power the return pad, Stewie's half-brother Bertram learns of the time machine and sneaks into the Griffin house to kill Stewie's ancestor to prevent him from being born. Unfortunately, as Stewie and Brian discover, by preventing the former from being born, then Stewie would not have been able to start the Big Bang, thereby creating a paradox that begins to wipe everything from existence. Brian and Stewie go back fifteen minutes earlier to stop Bertram from killing Stewie's ancestor, revealed to be Leonardo da Vinci. After a vigorous fight, Bertram has all three of them at crossbow point. Despite being warned that he could destroy all existence, Bertram does not care and shoots da Vinci. In rage, Stewie stabs Bertram.Despite the fact that da Vinci is dead, the universe is still existing. Stewie then concludes that he must be his own ancestor. He sends Brian back to the present, where a letter from the Vatican arrives, detailing that Stewie has buried himself in a cryogenic tube underneath the Griffin household. Once he is unearthed and thawed, Stewie informs Brian he put his DNA into a syringe and injected it into da Vinci's girlfriend.