Shredderville

"Shredderville" is an episode of the 1987 Teenage Mutant Ninja Turtles cartoon series.

Synopsis
The Shredder gets away once again, and the turtles believe that the world would be better if they weren't around. The Turtles wake up, discovering that Splinter and their lair are gone, and that New York City has been renamed "Shredderville". Donatello theorizes that they have somehow been dislocated into an alternate reality, a parallel earth where events unfolded slightly differently than on their own Earth, namely that the Turtles never existed in this world. Shredder was able to conquer New York, and presumably the entire world. Bebop and Rocksteady are humans, and Krang is a powerless alien brain without a robot body (because, without the Turtles to oppose him, Shredder never found the need to mutate Rocksteady and Bebop, or to build a robot body for Krang). New York City/Shredderville and the Technodrome have seen better days; poor maintenance has left the Technodrome a wreck in danger of exploding, and would likely take most of the city with it. Shredder makes numerous public announcements blaming mutants for all the problems in the city so they won't blame his incompetent administration. April O'Neil and Irma are servants of Bebop and Rocksteady, while Krang is a bureaucrat. When the Turtles confront Shredder, they find him to be overwhelmed by the problems of serving as administrator for the entire world and begs the Turtles to take him to their world, where he doesn't rule. The Technodrome blows up, and then the Turtles wake up they find out that all was a dream. They are unsettled to realize, however, that all four of them shared the same dream.

Upon learning their lesson from the dream, the Turtles stop wishing they weren't around.

Trivia

 * This episode is one of the few times during this series Shredder is pictured outside his battle armor. He wears only the helmet and face mask from his combat armor, and is clad in a business suit.
 * Dorian Harewood Voices Shredder.