The Justice League's war with the evil Perpetua comes to a shocking end, wiping the Justice League from the universe. But can they return?

Could Flashpoint have ended differently elsewhere in the Arrowverse? One theory suggests changes to Earth-16 could be the result of their Flashpoint.

"Spyfall," the season 12 premiere of Doctor Who, saw The Doctor erasing the memories of her historical companions after their adventure was over.

The X-Men reboot just rewrote Marvel history, turning a single Mutant massacre into the day their entire race was almost wiped from Earth.

Eternal Sunshine of the Spotless Mind is one of the most unique cinematic love stories of all time. The film stars Jim Carrey and Kate Winslet as lovers who break up with each other and both decide to have an experimental procedure done to erase the other from their memories. Thanks to the performances, the visually inventive direction from Michel Gondry, and a mind-bending script from Charlie Kaufman; the film is, ironically, unforgettable.

Star Wars is an incredibly expansive universe, one of the largest in all of entertainment media. There are thousands of worlds, characters, and creatures to learn about that an entire lifetime wouldn't be enough. When Disney purchased Lucasfilm for over $4 billion in 2012, years upon years of new films began development, not to mention all the supplemental books, television shows, games, and other materials. But to have a clean slate, the company decided to restructure their canon.

When Disney purchased Lucasfilm and announced new movies were on the way, all of the stories of this so-called Expanded Universe were invalidated, paving the way for the new, original stories that will be told on the big screen.