"Weirdmageddon Part 1" is the 18th episode of the second season of Gravity Falls and the 38th episode overall. It premiered on October 26, 2015 on Disney XD. This is the first episode in the Weirdmageddon story arc.
Trapped in the apocalypse and menaced by villains new and old, Dipper finds himself in a race against time.
The episode opens up right where the previous one left off, with Bill Cipher laughing at the gateway between the Nightmare Realm and Gravity Falls. His body gains flesh, metal, and pure energy as Bill finally obtains a physical form, becoming a triangle of light. Blendin Blandin sees the chaos above, and is helpless to watch as Mabel's unconscious body is lifted up and sealed in a pink bubble emblazoned with a shooting star. Chains wrap around the bubble, trapping Mabel inside. Blendin, struggling to comprehend what just happened, taps his wristwatch, informing the Time Paradox Avoidance Enforcement Squadron of the situation before he teleports away.
The townspeople of Gravity Falls all look up to the sky in fear as Bill grows in size, becoming a rotating pyramid-like abomination with six arms and a pure black form with multicolored energy. Bill returns to his normal form and floats down to the town, announcing that he will be the lord and master of Gravity Falls for eternity. He then melts a statue of Nathaniel Northwest as the townspeople watch in despair. Bill introduces the town to the other residents of the Nightmare Realm that Bill calls his friends, each more grotesque and anomalous than the last; 8 Ball, Kryptos, Zanthar, Teeth, Keyhole, Hectorgon, Amorphous Shape, Pyronica, Paci-Fire, and a large army of Eye-Bats Bill calls "these guys." The townspeople don't react kindly to the display, urging Bill and his friends to get out of town. Preston Northwest offers to join Bill and become one of his "horsemen of the apocalypse," but Bill switches all the orifices on Preston's face instead, laughing as the crowd runs away in horror. Bill promptly unleashes the winged eyeballs and madness bubbles all over town. The eyeballs petrify and abduct the townspeople, and the bubbles instill madness in everything they touch. Bill also summons a gargantuan black pyramid from the ground to serve as his castle and animates the Gravity Falls water tower. After proclaiming that time is dead and meaning has no meaning, Bill welcomes everyone to Weirdmageddon while the remixed theme song plays.
Meanwhile, Dipper and Ford watch the madness from the Mystery Shack. A massive group of animals, including the gnomes and a Manotaur, stampede out of the forests and away from Bill, knocking Dipper over. Ford picks Dipper back up, telling him that with every passing minute, Bill's dimension leaks into theirs and his power grows. Dipper thinks that the interdimensional rift must have cracked in his backpack when Mabel carried it, putting her in danger. He runs off to go find her, trying to contact her through their walkie-talkies. Ford stops Dipper and tells him that before they can find Mabel, they must defeat Bill. Their best shot is to knock him back into the rift from where he came before Weirdmageddon spreads across the entire world. Ford isn't sure it's possible, but says he has to try. Dipper and Ford abruptly stop when a gnome announces that a "weirdness wave" is headed their way. They rush inside the Shack as a giant pink tsunami washes over the entire town. The weirdness wave spawns a tentacle in Soos' backyard, makes his grill turn into a monster, and it turns Abuelita into a chair. Soos is shocked, but Abuelita tells Soos to go help the others around town. Soos follows her order and heads off. At the Shack, Stan is yelling at Gompers for chewing on his fez's tassel, threatening to get him off the premises. The weirdness wave causes Gompers to grow to an immense size, and Stan runs away with Gompers in pursuit. Next, the wave washes over the arcade, bringing Rumble McSkirmish and other arcade characters to life.
Meanwhile, in the Gravity Falls Maximum Security Prison, Lil' Gideon and the other inmates have made finger-paintings to share with each other. After the counsellor in charge of the event accuses Gideon's Mabel-centric art of being abnormal, the other inmates rally to Gideon's cause and back him up. They chant Gideon's name until Gompers chews through the prison walls, creating an escape route. After seeing the mayhem and madness going on across town, Gideon comments on how "Bill came through." Bill and his friends gather around the center of town, ready to cause more havoc. Dipper and Ford have followed them, hiding at the top of the Gravity Falls church. Ford has brought a black suitcase labelled "EXPERIMENT 618" with him.
Inside is a quantum destabilizer, a powerful gun that will have the ability to knock Bill back through the rift and shut down Weirdmageddon if he can aim the gun correctly. With the gun only armed for one attack, Ford locks Bill in his sights. However, the weirdness wave causes the bell in the church to personify, ringing of its own accord and causing Ford to miss the shot. It fires through Bill's top hat, sailing into a tree. Bill instantly regenerates the damage done to his hat and spots Dipper and Ford, firing a laser right through the church tower that obliterates it instantly. The two survive, but are badly injured. Ford, pinned under rubble, tosses Dipper a bag with the three journals inside. Ford begins to tell Dipper that there's another way to defeat Bill, but he is cut short when Bill appears, towering over Ford. Dipper manages to hide before Bill can spot him.
Bill captures Ford and presents him to his friends, telling them that Weirdmageddon wouldn't be possible without Ford. Bill makes an offer with Ford and tells him it's not too late to join Bill's side. Ford refuses, saying he'd rather die, so Bill turns him into a golden statue to use as a back-scratcher. Dipper, who has gotten back to street-level, yells that he's had enough. Bill flies over to Dipper, asking him what he could possibly do to defeat Bill in one shot. Dipper flips through Journal 3, trying to find Bill's weakness. With no answers, Dipper panics, and leaps towards Bill, trying to punch him. In response, Bill knocks Dipper backwards, causing him to fly into a tree. Bill then telekinetically seizes the three journals, burning them in front of Dipper, with two crippled pages surviving. After Bill shows Dipper the statue of Ford, saying that this is what happens to heroes in his world, Bill tells 8-Ball and Teeth that they can eat Dipper for a snack. Bill then converts a random car into a sleek getaway ride for himself and his other friends. The car flies away to the Fearamid leaving Dipper, 8-Ball, and Teeth behind. The two beasts chase Dipper into the forest as what's left of the journals blows away in the wind.
Three days into Weirdmageddon, Gravity Falls has become a complete wasteland. Shandra Jimenez reports the weather as the winged eyeballs petrify more and more townspeople. Dipper evades the eyeballs, calling Mabel via walkie-talkie. He talks to her about how he hasn't found her or Stan and isn't even sure she can hear him. Dipper decides to go to the mall, wondering if there are other survivors there. On the way, he runs into The Horrifying Sweaty One-Armed Monstrosity, who wants Dipper to "get into his mouth." As Dipper tries to open the mall's locked doors and the Monstrosity gains on him, its hand pushes Dipper through the doors.
As Dipper wanders around the mall looking for his family, he finds a tray of nachos in the food court. As he moves to pick them up, he triggers a trap and is caught in a net. Wendy reveals herself from inside a potted plant to examine her trap but is surprised to see Dipper. She frees him from the net and tells Dipper how she's been trained yearly at Christmastime to handle apocalyptic scenarios such as this. Dipper and Wendy hug, happy they have each other. Wendy also reveals she ran into Toby Determined earlier, who joins their group. They then escape to Wendy's secret hideout. Wendy tells Dipper that Robbie, Lee, Nate, Tambry, and Thompson were all petrified before she found Dipper. Dipper explains Ford's apprenticeship offer and his fight with Mabel to Wendy, who then invites him onto the rooftop of their hideout. As they survey the weirdness around them, Dipper mournfully tells Wendy they lost the battle against Bill. Wendy gives him a pep talk, saying it's not over yet and that he needs to get Mabel back if he wants to defeat Bill. She tells Dipper that when he and Mabel are together, there's nothing they can't do. Dipper realizes she's right, but he still doesn't know where Mabel's bubble is. Suddenly, a billboard blocking the view is eaten by a monster, which reveals Mabel's location: right near the Floating Cliffs. Wendy comes up with a plan to get to Mabel's bubble.
Meanwhile, Bill and his friends are having a rave party inside the Fearamid. They're playing party games with the statues of the Gravity Falls citizens. Bill tells his friends that once the party is over, he'll unveil Phase 2 of Weirdmageddon. Suddenly, the Time Police, Blendin, and Time Baby barge in, crashing the party. Lolph, Blendin, and Time Baby accuse Bill of possessing Blendin and almost destroying reality. Bill vaporizes the Time Police holo-projections and Time Baby instantly, and the party resumes. Blendin escapes unharmed and teleports away. 8-Ball and Teeth approach Bill, worried that Dipper might foil their plans. Bill says he's not worried, and that he has "someone on the case." Dipper and Wendy break into the abandoned auto mart, planning to hotwire a car and use it to get to Mabel. Toby tries to steal an air freshener but is knocked unconscious by tranquilizer darts. Dipper and Wendy are accosted by the Discount Auto Mart Warriors, a group of escaped inmates led by Gideon himself. Dipper tries to explain that they just want one car, but Gideon interrupts, telling them that Bill himself has ordered Dipper and Wendy to be put under arrest.
Gideon explains that Bill has appointed him as the master of the wastelands so that he could watch over Mabel's bubble. He also shows that he has a key that can unlock her bubble. Gideon is ecstatic over his new job, and he still believes that Mabel is destined to be his. Gideon then tells Ghost-Eyes to bring Dipper and Wendy to Bill. Before he does so, Wendy attacks Ghost-Eyes and steals the key from Gideon. She then dropkicks Gideon into a crowd of Warriors and drives off with Dipper. The Warriors take Gideon and start following them. Wendy tells Dipper that she doesn't have a license while she swerves around the Monstrosity. Gideon's henchmen aren't so lucky, and the Monstrosity manages to eat a car. Ghost-Eyes and Gideon escape as Ghost-Eyes questions why Gideon is keeping Mabel in her bubble. Dipper and Wendy notice a group of weirdness bubbles up ahead, which they have no choice but to drive through. Their animation styles change drastically in each bubble they go through, ranging to becoming birds to anime to live-action. Gideon and his henchmen travel through the bubbles as well, still in pursuit.
Eventually, the two parties are neck-and-neck. Gideon begins to crash his car into Dipper and Wendy's. Dipper realizes that they are close to Mabel's bubble, but have to make a gigantic jump across a canyon. Wendy manages to avoid Gideon's attack and drive the car across the canyon. However, the car crashes and rolls across the ground, heavily injuring Dipper and Wendy. Dipper crawls out of the car but bumps into a mysterious hooded figure that reveals themselves to be Soos. Soos tells Dipper and Wendy how he's been wandering across the plains and helping strangers in need. He also reveals that Gideon and his henchmen have surrounded Dipper and Wendy. Gideon then summons an army of Bill's Eye-Bats to retrieve Dipper and his friends, proclaiming that Mabel is his. Dipper then tells Gideon that Mabel doesn't love him, and never did. He continues to say that Gideon can't force Mabel to love him, but he can try to become someone worthy of loving.He tells Gideon that if he stands up to Bill and lets Dipper free Mabel, that would make him a better person and would make him better in Mabel's eyes. Gideon decides to help Dipper but says that he has to tell Mabel that Gideon helped set her free. Dipper accepts, and Gideon and his henchmen drive away to fight Bill's Eye-Bat army. Dipper, Wendy, and Soos make it to Mabel's bubble and unlock it with the key. Dipper warns his friends that they have no way of knowing what dangers Bill has put inside, but they know they have to do it for Mabel. They walk inside the unlocked bubble as the foreground fades to white, with "To be continued..." appearing at the bottom of the screen.
In the end credits, the monstrosity is attempting to get people into his mouth, but his actions end in failure. He resigns himself to a fate of starvation, crawling off screen to call his mother.
- Directed by:
- Additional Written Material by:
- With the Voice Talents of:
- Jason Ritter as Dipper
- Alex Hirsch as Grunkle Stan, Soos, and Bill
- Louis C.K. as The Horrifying Sweaty One-Armed Monstrosity (original version)
- J.K. Simmons as Ford
- Will Forte as Tyler Cutebiker
- Danielle Fishel as Pyronica
- Patrick McHale as Hectorgon
- Andy Merrill as Teeth
- Brian Bloom as Rumble McSkirmish
- Jennifer Coolidge as Lazy Susan
- Carl Faruolo as Grenda
- Jackie Buscarino as Pacifica Northwest
- John DiMaggio as Manly Dan
- Nathan Fillion as Preston Northwest
- Linda Cardellini as Wendy
- Kevin Michael Richardson as Sheriff Blubs
- Justin Roiland as Blendin Blandin
- Thurop Van Orman as Li'l Gideon
- Dave Wittenberg as Time Baby
- Gregg Turkington as Toby Determined
- Additional voices:
- Casting by
- Wendy has always wanted to drive a tank.
- Dipper and Mabel have allergies that go off at the same time.
- Ghost-Eyes majored in philosophy.
- The Corduroys train for the end times instead of celebrating Christmas.
- Bill has been trapped in a decaying dimension for one trillion years.
- Wendy never got her driving license.
- The episode continues immediately after "Dipper and Mabel vs. the Future," following Bill's success in opening a gateway to the Nightmare Realm.
- In "The Last Mabelcorn" Bill says, "I've been making deals, chatting with old friends, preparing for the big day." This foreshadows the entrance of Bill and several other demons into Gravity Falls during Weirdmageddon.
- Bill also refers to Dipper as "his old puppet," referencing the events of "Sock Opera."
- The snake and the badger from "The Love God" make an appearance running out of the forest.
- Chutzpar, the Manotaur from "Dipper vs. Manliness," is seen fleeing the forest with other animals.
- Tyler Cutebiker is shown as Gravity Falls' mayor after winning the election in "The Stanchurian Candidate."
- Rumble McSkirmish reappears when the Arcade is flooded with a weirdness wave.
- Gideon is shown to still have possession of the newspaper clipping of him and Mabel seen in "The Hand That Rocks the Mabel."
- Bill burns all three journals except for a single page which is then blown away.
- The Pterodactyl from "Land Before Swine" can be seen on top of Gravity Malls.
- There are parts of Hoo-Ha's Jamboree by Toby's feet when he is shown with an arrow in his arm.
- The water tower still has a hole in it from the security pod crashing through it in "Dipper and Mabel vs. The Future."
- The Blind Eye symbol can be seen on the fence when Dipper is hiding from the Eye-Bats.
- The time at Gravity Falls stops at 3:00 PM in August 23, 2012 (Bill states that time is non-existent) when Weirdmageddon happens; although in the next episode "Weirdmageddon 2: Escape From Reality", it's revealed that it has been at least four days since the event began.
- A remixed, apocalyptic version of the theme song is used for this episode where Bill and his friends replace the main characters in every shot.
- At the end of the opening theme, a faint whisper can be heard that is different from the ones heard throughout the show. When the theme is reversed, Bill can be heard saying "I'M WATCHING YOU NERDS."
- 618 appears on the truck driven by Ghost-Eyes and Gideon.
- In the Polish version of the show Bill calls Weirdmageddon "Showmageddon" it's unknown why.
- The box that contains Ford's quantum destabilizer is labeled "EXPERIMENT 618." Notably, the electron rug from Carpet Diem is also called Experiment 618
- The weirdness bubbles that Dipper and Wendy go through turn them into birds, anime, meat, and live-action versions of themselves. The weirdness bubbles Gideon and Ghost-Eyes go through turn them into polygonal, female, and silent film versions of themselves.
- Jason Ritter and Linda Cardellini portray the live-action versions of Dipper and Wendy.
- One of the early character concept art for the Cyclops from "Little Gift Shop of Horrors" was used as a purple-colored monster that appeared in this episode. 
- Originally, Bill was going to sing a song about Weirdmageddon titled "It's Gonna Get Weird." The song was written, but it was cut for time (since Weirdmageddon was so action packed, they couldn't find the time to include the song, but the song can be found on YouTube).
- This is the only full-length episode of the series in which Mabel does not speak.
- When Alex Hirsch first announced the episode's airdate, he gave the title as "Xpcveaoqfoxso," which is "Weirdmageddon" coded into the Vigenère cipher with the keyword, "BLUEBOOK" (the keyword from "Dipper and Mabel vs. the Future"). "Xpcveaoqfoxso" is the episode's official title in international broadcastings, and many TV listings use this title as well.
- After Louis C.K. admitted to sexual misdemeanors, Alex Hirsch redubbed the character of The Horrifying Sweaty One-Armed Monstrosity for airings of the episode after December 19th, 2017. Amazon video and iTunes changed their digital copies of the episode to the redubbed version as well.
- The cryptogram in the episode's credits reads, "KB HTMT IHOV 1,000 AMLCT NDY XZOM MLCG'H TSCGKFWFA IV VVEWYDUQIBXV CVO HIMC OI'J DINV, IM'H NSZPO EZ CM KLVP EZLYLG." It reads "IT WILL TAKE 1,000 YEARS FOR TIME BABY'S MOLECULES TO RECONSTITUTE. AND WHEN HE'S BACK, HE'S GOING TO BE VERY CRANKY."
- The Keyword: CILLBIPHER can be found on a wall
- The title card flickers from "Gravity Falls" to "JUDYLWB IDOOV," which, when translated with the Caesar cipher, says, "GRAVITY FALLS."
- This also appears in the Water Tower in a short second where the screen turns static.
- The cryptogram in the episode's end page reads, "17-23-11-19 15-5 9-2-19-6, 23-10-20 15 1-9-10. 10-9-1 15-4'5 4-15-11-19 4-9 5-4-23-6-4 4-16-19 18-3-10. 15 23-12-1-23-25-5 12-9-2-19 21-9-6-6-3-8-4-15-10-17 12-15-2-19-5. 10-9-1 12-19-4'5 5-19-19 1-16-15-21-16 8-15-10-19-5 5-3-6-2-15-2-19-5." Once decoded using the combined cipher it reads, "GAME IS OVER, AND I WON. NOW IT'S TIME TO START THE FUN. I ALWAYS LOVE CORRUPTING LIVES. NOW LET'S SEE WHICH PINES SURVIVES."
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