Weirdmageddon

Weirdmageddon, also known as the Oddpocalypse, is an apocalyptic event that occurs in the animated show Gravity Falls. Prophecized millennia before the events of the series, this event sees the arrival of the two-dimensional demon Bill Cipher, who unleashes absolute chaos upon the world.

History
Eons before the events of Gravity Falls, the chaotic entity Bill Cipher waited for the time when a rift would open between the Second and Third Dimensions. In the meantime, Bill could reach out through the Mindscape to communicate with the inhabitants of the Third Dimension. Through these communications, the early inhabitants of the area that would become known as Gravity Falls, Oregon learned of Bill's existence and came to worship him as a god. Even into the modern era, evidence of the prophecy could be found all over the region, though few understood its meaning by that point. During the late 20th century, paranormal researcher Stanford Pines had come to Gravity Falls to investigate the bizarre phenomena present in the region. Bill, observing from his own dimension, recognized that Ford's brilliant but cocky and insecure nature and near-friendless background made him an ideal pawn. When Ford accidentally stumbled into a strange cave, he discovered a painting about a "being with answers". Desparate and naïve, Ford ignored the warnings and read the summoning inscription, but was confused when nothing happened. Later that day, while taking a nap, Bill entered the man's dreams. Bill deceived the man, telling him that he was a muse who chose one incredible person every hundred years to inspire. He told Ford that if he sided with Bill, they would unlock the greatest riddles in existence. Blinded by this flattery, Ford believed Bill to be a friend and agreed to the deal.

Once Cipher had tricked Ford into befriending him, he told him to build a great machine which he claimed would create knowledge to benefit all mankind. However, when the time came to test it, one of Ford's human friends, Fiddleford McGucket, was sucked into the machine and discovered its true nature: a portal into Bill's world that would allow the demon to bring his chaos into their universe. Horrified and betrayed, Ford shut down the project and hid the instructions on how to operate it. Bill, however, could not be so easily deterred and patiently waited for the time when the portal would reactivate. As Bill waited for his opportunity, the portal was reactivated twice. The first of these instances was in 1982 when an argument ensued between Ford and his twin brother Stanley. Ford had called upon his estranged brother to assist him in destroying the portal machine, but the twins got into a fight and accidentally activated it, resulting in Ford being sucked into the portal and sent to an unknown part of the Multiverse. Blaming himself for his brother's disappearance, Stan worked to understand how the machine operated so that he could bring Ford back. Thirty years later, he succeeded and Ford returned to Earth. However, using the portal had created a small interdimensional rift that could potentially allow Bill through into the Third Dimension. Ford was able to contain the rift in a snowglobe-shaped vessel, but knew that he was only delaying the inevitable and sought to find a way to completely close the rift while at the same time taking steps to protect his home from Bill's chaos.

As the summer of 2012 drew to an end, Mabel Pines - Stan and Ford's grand-niece - became upset as she hadn't been able to get anyone to agree to come to her and her twin brother Dipper's 13th birthday party. Not only that, but Dipper had been considering staying in Gravity Falls to become Ford's apprentice, and Mabel hated the idea of going back home to California without him. She ran away from the Mystery Shack, taking Dipper's backpack with her which contained the rift in its glass bubble. Out in the woods, she encountered Blendin Blandin, a time-traveller she and Dipper had previously met. Having overheard Mabel crying about wanting summer to last longer, he offered her the chance to make that wish come true if she gave him the rift bubble in exchange. What Mabel didn't know was that Blendin had been possessed by Bill Cipher, who smashed the rift container as soon as he got his hands on it. With the rift no longer contained, the sky above Gravity Falls tore open as Weirdmageddon began. Bill gained a physical form as he descended from the rift and unleashed all manner of chaos and weirdness upon the town, backed up by hordes of monsters that emerged after him. Within three days, Gravity Falls had become unrecognizable: the town lay in ruins, Eye-Bats and other creatures ran amok and a giant, floating structure known as the Fearamid hovered above the burning town where Bill and his Henchmaniacs partied night and day. Most of the townspeople had been turned to stone and their petrified bodies had been arranged to build a throne for Bill.

Eventually, Bill decided to take Weirdmageddon across the globe, only to find that he couldn't. Ford Pines had created a mystical ward around Gravity Falls that prevented Bill and his cronies from venturing beyond the town, and so Cipher attempted to force Ford to reveal how to breach the barrier.

On the fourth day of Weirdmageddon, Dipper and Mabel Pines, their Grunkle Stan, their friends Soos and Wendy and an assortment of survivors and local creatures, banded together to stop Bill. With the help of Fiddleford McGucket, they converted the Mystery Shack into a giant robot and used it to storm the Fearamid. While Bill and his hench-maniacs were distracted fighting the Shack-Bot, a rescue team consisting of Dipper, Mabel, Stan, Soos, Wendy, McGucket, and Pacifica Northwest infiltrated the Fearamid. Bill fought the giant robot shack, but could not damage it due to the magical unicorn hair barrier. Bill eventually discovered that the barrier didn't extend to the robot's legs, so he exploited that weakness to destroy it. With aid from the captured Gideon Gleeful, the rescue team saved Bill's captives, including Ford. After a happy reunion with his niece and nephew, Ford explained that the way to thwart Bill was by using a zodiac with ten symbols. Each image represented a person, and once all ten people were gathered and holding hands, Bill could be defeated once and for all. For a moment, it seemed that Dipper, Mabel, Soos, Wendy, Gideon, Old Man McGucket, Robbie Valentino, Pacifica, Ford, and Stan would succeed, but at the last moment, Ford and Stan began arguing. Bill took this opportunity to prevent the zodiac wheel from activating.

Bill turned all but Mabel, Dipper, Stan, and Ford into tapestries, trapped the men in a cage, and angrily chased Dipper and Mabel through the Fearamid after Mabel sprayed paint in his eye to distract him. After recapturing the twins he gave Ford an ultimatum--let Bill into his mind, or Mabel and Dipper would die. Ford reluctantly agreed, shook the demon's hand, and let Bill into his mind. However, Bill was shocked to realize that he, master of trickery and manipulation, had been deceived. He had not entered Ford's mind at all, but Stan's. While the demon was distracted chasing Dipper and Mabel, the brothers devised a plan to destroy Bill once and for all. They tricked Bill into going inside Stan's mind instead of Ford's by changing their clothes and impersonating each other and then Ford would shoot Stan with a Memory-erasing gun which would completely wipe away Stan's mind and erase Bill from existence. Bill was trapped inside Stan's mind and started begging for his life, promising Stan anything he'd ever want. Stan wasn't swayed and watched as his mindscape began to burn away and Bill's form violently distorted. As Bill reached out to him, Stan punched the demon right in the eye, destroying him.

With his dream essence destroyed, Bill's physical form turned to stone and all of the chaos he had unleashed on Gravity Falls began to disappear. The monsters that had followed Bill were all pulled back through the dimensional rift, which closed forever behind them. Gravity Falls and its townspeople had been restored to normal and Bill's threat to the universe had been averted.