The Joker wandered around his cell in Arkham Asylum, pondering his latest defeat at the hands of his long-time nemesis. He paced back and forth, wondering why all his schemes never seemed to work. It was the same every time: he'd have some crazy scheme to cause havoc and take over Gotham, and Batman would come and stop him. Then he'd be thrown in Arkham and the cycle would repeat itself. But The Joker wanted more. He was sick and tired of being defeated time and time again.

"I need something new" he thought to himself. "It's apparent that no matter how many times I try, I'll never take over Gotham. But, perhaps there is something else I can do. This universe of cartoons is huge, and there are other villains in other realms that are probably thinking the same thing I am now".

Then an idea came to him, and he laughed maniacally.

"That's it! Why didn't I think of this before? I'll create a new realm all for myself! I can rule there and never have to worry about Batsy stopping me! Hoo hoo, it's the perfect plan! However, I'm not going to be able to do this alone"

He thought for a moment, and then snapped his fingers when he got the new idea.

"I've got it! I'll send out a message to four other villains for other realms with talents that could help me achieve my goal. I've heard about these specific four, and it seems that if we all joined together, we would be unstoppable. But, first I'm going to have to break out of here".

He laughed to himself at how easy that would be, and started planning his escape. By the end of the day, he had escaped from Arkham and was in his hideout, instructing his top men to send a message to the other villains. A scientist he had kidnapped had created a machine that would send the message to the other realms.

The message read, "Dear villains, I am sending you this message because I require your help. You see, I am tired of constantly being defeated by my nemesis, and I assume you all feel the same way. Therefore, I have a plan to create a new realm, one for us villains to have for ourselves! However, I need your help to make this dream a reality. Equipped with this letter you will find a small device that resembles a remote. It will allow you to travel to different realms of the cartoon universe. If you agree to help me with this endeavor, then use the device to come to the old abandoned wharf in Gotham City. I will be awaiting your response. Sincerely, The Joker".

He sent the message and the devices to the four other villains and waited. After about a half hour he got four replies, all saying that they would help. The Joker smiled and called to his goons.

"Boys, prepare the place for our guests. My master plan is about to unfold".

His goons went off to make the place look nice and The Joker laughed evilly to himself.

Soon later, each of the villains arrived in The Joker's hideout. They were Terrance, from Totally Spies; Discord, from My Little Pony: Friendship is Magic; Dr. Heinz Doofensmirtz, from Phineas and Ferb; and Dr. Eggman, from Sonic X. The all took a seat as The Joker explained his plan.

"Thank you all so much for coming, I guarantee you will not be disappointed. Now, let's get down to business. My master plan, as I said in the message I sent you all, is to create a new realm for us to rule in, without having to worry about our enemies. Here's how we're going to do this: Drs. Doofensmirtz and Eggman, I need you two to create a machine that can create a new realm in the cartoon universe. We already have a device where we can go from realm to realm so that's not a problem. But before you do that, I want the heroes from each of your realms captured, so they can't stop us. I think it will be better if each of goes into a realm other than our own. That way, the heroes won't know what hit them when they see a new villain. So, Eggman, you go to Beverly Hills. Doofensmirtz, you to Equestria. Discord, you go to Danville. And Terrence, you get to go to Gotham. As for me, I'll take Central City. Any questions?"

The other villains shook their heads.

"Alright then" The Joker smiled, "Let's move out!"

The villains used their devices to teleport to their assigned realms. One thing now was for certain: the cartoon universe would never be the same again.