Inspired by Fallout: Equestria written by Kkat.

Fallout: Foster's Home

Peaceful co-existing was not guaranteed for us, but we didn't know it. Relationships between humans and imaginary friends were quickly falsely accused when the worst imaginary friends of all, Extreme-o-sauruses, suddenly rampaged and terrorized everything.

Everyone across the globe was either in panic or blinded by rage and revenge from the savage beasts, and sought to use nuclear weapons to destroy them all.

But the resulting detonations not only killed off most of the Extreme-o-sauruses, it also killed off millions of innocent lives. No one knows for sure if it was by accident or intentional, but the aftermath was devastating. The planet's atmosphere was becoming poisoned from the nuclear blasts, causing all plant life to become intoxicated. The resulting decline in plant life not only eliminated a large portion of numerous ecosystems, but also nearly made breathing on the surface a death wish.

So, people and non-Extremes were forced into underground military and naval bases for protection, in hopes of repopulating Earth once it was clean and safe again.

But Madame Foster had the same idea. She moved all of her beloved imaginary friends into a secret TARDIS-like toy chest, where another imaginary friend named World could protect and watch over everyone.

And now, after so much time that everyone has forgotten how long they have been inside, the residents of Foster's Home for Imaginary Friends live a normal and safe life in the toy chest.