Ret-Gone/Western Animation

Examples of in  include:


 * In Beast Wars, if Megatron's scheme had worked out, the entire Maximal race would have been negated from history and would never have existed. However, it's revealed in the video game of the series that, had his scheme worked, For Want of a Nail would've kicked in, dooming the Decepticons, their ancestors, as well, because without Optimus Prime there would be no Matrix of Leadership to stop Unicron from chowing down on Cybertron.
 * Subverted in the Futurama episode "Roswell that Ends Well". Fry travels back to the 40's, meets his grandfather Enis, and becomes convinced that any harm that befalls Enis will result in his own non-existence. (Fry even claims at one point "I could feel myself beginning to fade away!") Then Fry's meddling accidentally results in Enis' death, and Fry is surprised to find himself still in existence. As it turns out, a Stable Time Loop is in effect, and Fry is his own grandfather.
 * Another time travel episode has another subversion: In this episode, you can only travel forward in time, albeit at any speed you desire. You can travel backward by going through one Big Crunch and another Big Bang, and as a result there's a universe out there with no Nazis.
 * In one episode of Danny Phantom, Sam gets in a fight with Danny and wishes they had never met. In the presence of a wish-granting ghost. Take a wild guess what happens. Sam herself is unaffected, thanks to a Fenton Device. It's revealed that she's directly responsible for his powers (and his snazzy new shirt logo). The fading-photograph trope (resulting in awkward gaps that wouldn't've actually happened) features heavily (although why the warded copies were on her person in the first place... just go with it). While in the presence of the wish-granter again, she managed to wish everything back to normal (relatively speaking), except for the outfit.
 * Although it is the relationship that is retgonned, not any person. In contrast, when Danny stops his parents from meeting, Jazz was retgonned.
 * In Tripping the Rift, Chode and Gus travel to the beginning of time to witness the creation of the universe, and accidentally kill God, Retgonning his influence from the universe. Upon returning to their own time, Hilarity Ensues.
 * It was actually rather pleasant, up until Chode and Gus brought in the concept of evil with them, which caused an immediate death spiral for all life everywhere. The reason why? Well, with no God to tell people what NOT to do, no one ever had the idea of doing anything bad. No God, No Evil. But once the concept of "Evil" was brought in from the outside, with no fear of divine punishment for any crimes you commit, well, there's no reason NOT to do terrible things, up to and including senseless murder.
 * Ren and Stimpy: This happens to Captain Hoek and Cadet Stimpy (and the narrator) in "Space Madness", after Stimpy pushes the History Eraser Button, which turns out to be Exactly What It Says on the Tin.
 * In "Yesteryear" by DC Fontana, the most popular episode of Star Trek: The Animated Series, Spock is temporarily Ret-Gone until he creates a Stable Time Loop preventing his death as a child. Interestingly, it involves a change from the original timeline.
 * One episode of the Men in Black Animated Adaptation dealt with a crazed alien enthusiast finding a way to time-travel and going back to kill off the founding members of the eponymous organization. A photo displaying the meeting between the founders and a group of aliens has each human disappearing one by one, and everyone instantly forgets them except Jay, who's gained Ripple-Effect-Proof Memory via some Alien Phlebotinum which is also slowly killing him.
 * Taken Up to Eleven on Family Guy, when Stewie learns that his time machine accidentally created the universe, but Bertram kills Stewie's ancestor. Stewie sets everything right, though, since Status Quo Is God and they've already done the Gainax Ending to death.
 * And in another episode, tried to do this to himself with his rebuilt Time Machine after getting too fed up to live with the rest of the family.
 * The Life and Times of Juniper Lee: In the episode "Te Xuan Me", Juniper prevented a thief from stealing dragon eggs. The thief then tried to get back in time to change this by using a secret time portal guarded at a clocktower where Juniper and her classmates went for a field trip. The portal was kept by time wraiths who captured Juniper and her classmates and reformed Earth without them. In the alternative timeline, Ray Ray was the Te Xuan Ze; Dennis behaved like the mainstream Ray Ray; and Monroe said Ray Ray accepted the Te Xuan Ze role better than anybody else he ever met. Ray Ray and the thief were the only people to remember the original timeline. Despite Monroe's protests, Ray Ray rescued everyone.
 * In the Gravity Falls episode "The Time Travelers Pig",  Blendin swears revenge against Dipper and Mabel for  stealing his time travel device and ruining his life, swearing to go back in time and prevent their parents from meeting; one can assume he either changed his mind or failed to do so.
 * It is often debated among fans of Codename: Kids Next Door whether or not Sally (Numbuh 3's granddaughter from a Bad Future) inadvertently (or even purposely) prevented her own birth in "Operation: F.U.T.U.R.E." by helping to Set Right What Once Went Wrong If true, it may count as the most heroic of Heroic Sacrifices.