A Chaotic Team Up:

Within the deep forest, lied the statue of a, once powerful, demon. This demon was known as Bill Cipher. He was a terrifying entity that tricked people into bad deals and abused his powers as a dream demon. However, because of the barrier surrounding Gravity Falls, his power was limited.

During a special Summer in Gravity Falls, he had made it his goal to target a certain Pines family. He had caused them plenty of grief in many ways. For example; entering their minds, bringing traumatic nightmares, and even causing the apocalypse known as "Weirdmageddon".

Luckily, the Pines family put a stop to his plans. And now, he lies stuck as a statue, powerless and without a chance to return.

However, one day, someone of the same being as Bill had visited this statue. The being that appeared before the statue was that of a demon, coming from a portal in the air. He wore clothing like that of a Jester, as well as a mask that was half black, half white, and had a permanent grin carved upon it. The mysterious being investigated the statue, looking on with glee and amusement with his hands behind his back.

"Heh heh heh, looks like I've found you." The mysterious Jester then placed one arm in front of him, causing a dark energy to envelop the petrified Demon. The ground began to shake, cracks now forming on the stone. The cracks continued to form until- *SMASH!* the triangular demon had been freed, his previous rocky form now lying in pieces.

"Wooo! Bill's back in the game! My time of being a target for birds is over! Hahahah!" The dream demon shouted with joy, feeling the power he had long since lost after his "death". "Well, time for some good old fashioned revenge. I can't wait to see the Pines family's reaction. They're gonna lose it!" Before the Demon could go on with his plan, he felt a strange force drag him back to the ground.

"Hey, what gives?!" The demon asked, unknowing of the being who has brought him back in the first place. He eventually spotted the mysterious being out of the corner of his eye.

"Ah, ah, ah. I can't have you leaving just yet, Mr Cipher. I still have some plans I'd like to discuss with you." The mysterious being said, letting out a creepy chuckle as he waved his finger side to side.

"Well, well, well. That's a familiar face. Dimentio, haven't seen you since that time you bragged about destroying multiple universes at once. Have to say, that's some pretty impressive work." The demon chuckled, rising to the sky as he twirled his cane in one hand.

The two proceeded to engage in a conversation about their, rather morbid, feats of destruction and torture.

Once their conversation had come to a halt, Dimentio had taken a bit more of a "serious" tone.

"Well, now that our small talk has finished, how about I interest you in my plan? How does multiversal destruction and conquest sound to you?"

Bill had grown quite a bit amused at this statement. "I'm listening."

The Jester revealed a holographic image in the palm of his hand, revealing a whole series of different universes and galaxies. "You see, I had come quite close to having all of this under my command. However, a certain pesky plumber and his little friends had proved themselves to be quite the nuisance. I do have to admit, that mustached mortal was quite a deal more powerful than I had expected. He managed to defeat me, even when I had the power of his brother added to my own. Also, when I had caused the destruction of the universe at the end of our fight, he managed to survive even that. Then because of that annoying fairy and Count Bleck, the universe managed to restore itself. Seeing all of my hard work go down the drain was quite annoying, as you can tell."

The triangular demon had looked on, rolling his eye with displeasure. "I know that feeling. Because of the stupid Pines family and their tricks, I lost out on everything I worked for. I'll make sure they pay with their lives the next time I see them!" Bill yelled, his form changing into a demonic red color.

"Well, I think my plan might be able to help solve both of our problems. You see, if we were to work together, not even Mario or those twins would be able to stop us. The entire multiverse would be ours to mold and bend to our will. I believe that would be a most spectacular show, wouldn't you say? So, how about it?" Dimentio said in a dark tone, extending his hand to the triangular demon.

Bill had laughed in a maniacal tone, seemingly approving of the Jester's idea. "Buddy, you've got yourself a deal!"