"Weirdmageddon 3: Take Back The Falls" is the 20th episode of the second season of Gravity Falls, the 40th episode overall, and final episode of the series. It premiered February 15, 2016 at 7:00 PM on Disney XD and February 19, 2016 at 9:00 PM on Disney Channel.
This is the third and final episode in the Weirdmageddon story arc, as well as the one hour-long series finale. The second half of the episode is broadcast as "Weirdmageddon 4: Somewhere in The Woods" in subsequent re-airings for half-hour programming.
Part 1 - Weirdmageddon 3: Take Back The Falls
Dipper, Mabel, Wendy and Soos barge into the Mystery Shack to be greeted by the remaining refugees of Gravity Falls, including Stan Pines, Old Man McGucket, Pacifica Northwest, other townsfolk and mysterious creatures of the town. Dipper and Mabel are happy to see Stan, and they hug him with Soos and Wendy. The twins question why everyone is hiding out in the Shack, but before they can get an answer, an Eye-Bat sweeps the outside of the Shack, forcing everyone to hide once more.
Once the coast is clear, Stan shows Dipper and Mabel life in the Shack. The situation seems rather grim for the survivors; many of them are injured and food is becoming scarce. Stan shares his story to the twins: he was working outside when Weirdmageddon struck, and sought refuge in the Shack. He learned that the unicorn hair, Mercury and Moonstone barrier that Dipper and Ford set up around the Shack protected it from weirdness waves and all things related to Weirdmageddon. When McGucket showed up near the Shack with the refugees, Stan elected himself chief of Gravity Falls due to Tyler Cutebiker's absence and let them stay. His current plan is to hide out in the Shack until they run out of food, with eating the gnomes as a backup plan.
Dipper angrily informs Stan that Ford has been captured by Bill and that they cannot just stay cooped up in the Shack. Stan grudgingly shrugs the issue off, believing that Ford has to get himself out of the mess he made. Stan insists everyone will be fine in the Shack, and thinks that the rest of the townspeople will be fine on their own. However, a news broadcast from Shandra Jimenez inside the Fearamid shows the throne made out of petrified townspeople to the survivors for the first time. The refugees are shocked to see their loved ones turned to stone.
While the refugees are discouraged, Mabel and Dipper try and inspire them to fight back to save their friends, saying that Bill wants them to run and hide. Dipper says that Ford knows Bill’s secret weakness. If all of the refugees band together, they can rescue Ford, find Bill’s weakness, and save the town. The refugees are optimistic, but Stan objects on the grounds that the Shack is the only place safe from Bill and that there's no way to bring it to him. This gives McGucket an idea, but he says it will require everyone to work together. He puts on his goggles and begins to share a plan while Stan looks on uncomfortably.
Inside the Fearamid, Ford is reverted from his gold state inside a private study and chained to the floor. Bill Cipher rises up from the ground, playing a piano. He explains Ford is trapped inside a penthouse suite in the tip of the Fearamid. Ford deduces that Bill wants something from him. Bill explains that with his newfound powers, he can control all of space, matter, and time. He reveals that he used to live in the second dimension until he destroyed it, and is aiming to do the same to this one. The only problem is that he, along with the rest of his friends, can’t escape Gravity Falls. Ford thinks that this is due to a natural magnetism attracting weirdness to Gravity Falls, the event he’s studied for years, a force so strong that it forms a barrier that prevents that weirdness from going outside the town. He says there’s a way to break this barrier, but he’d never tell Bill. Bill tries to persuade Ford by telling offering him unlimited power in a world without restrictions or laws. Ford again refuses, calling Bill insane. Bill decides to find the equation needed to break the barrier in Ford’s mind. However, Ford reminds Bill he can’t unless he makes a deal with him. Bill decides to try and find Ford’s weakness and force him to make the deal, chaining him up further.
Back in the Shack, McGucket reveals the blueprints for his newest robotic invention. While the twins and the other survivors are impressed, Stan remains pessimistic. In spite of the odds, all of the refugees band together to assemble McGucket's giant mech using various materials found inside the Shack and elsewhere in the surrounding area.
Having made a flag for their resistance, the refugees sit outside around a bonfire. Mabel has knit special apocalypse sweaters for everyone, including a llama sweater for Pacifica which she begrudgingly wears. Mabel thinks that they might have a shot at defeating Bill. Dipper laments that the only birthday present he wants is to survive the summer. Soos assures Dipper that if they live, the entire town will throw Dipper and Mabel a birthday party. Dipper cheers up and wonders where Stan is. Stan is away from the crowd, ranting to Shmebulock about how the resistance’s plan is garbage and how no one’s listening to him. When Dipper and Mabel ask Stan what’s wrong, he shares his feelings about the plan. He doesn’t want to save Ford, as he’s still upset that Ford never thanked him for rescuing him. Stan does not understand why Ford is still called a hero, when it was Ford who brought Weirdmageddon in the first place. Dipper says that Ford is a hero because Ford did not want to hide, but Stan retorts that if Ford hid, then Ford would still be alive. Mabel breaks up the conflict, assuring everyone their plan will work.
The next day, everyone gathers inside the Shack with McGucket hoping his invention works. Dipper pulls a lever inside the Shack, causing mechanisms to activate that turn the entire Mystery Shack into a gigantic mech. The mech walks past some other survivors on its way to the Fearamid, where it’s shown that in the throne room, Bill and his friends are torturing Ford by blasting him with lasers. Ford is in pain, but doesn’t give in. Before Bill can start torturing Ford again, a dinosaur head busts through the door of the Fearamid, outraging Bill. Soos steps out onto a platform on the mech, dubbing it the Shack-tron. Bill finds it adorable the refugees are fighting back, and orders his henchmen to fight them. They increase their size and jump out of the Fearamid, ready to fight. Stan thinks the plan was a bad idea.
Soos tells the henchmen to hand over Ford, or else they’ll fight. The henchmen immediately rush the Shack-tron to battle. Inside the Shack-tron, the refugees control various mechanisms that control different parts of the actual mech, using weapons to fight against the henchmen. Rumble McSkirmish and Wendy attack outside the Shack-tron, with Rumble attacking from afar and Wendy piloting a rogue Eyebat to turn the henchmen to stone. Stan desperately tries to find an exit. Zanthar rushes the Shack-tron, pushing it through several stone walls. Using all of their power, the refugees control the Shack-tron to throw Zanthar into the distant mountains, subduing the henchmen.
Bill is upset as Ford congratulates Dipper and Mabel for their efforts. Bill realizes Ford cares about the twins, and wonders if torturing them will be more effective than torturing Ford. Ford is turned back into a gold statue as Bill flies over to the Shack-tron and attempts to crush it with a giant fist. However, it remains intact thanks to the unicorn barrier. Bill becomes enraged and repeatedly punches the Shack-tron. The refugees use the dinosaur arm to tear out Bill’s eye and distract him. Realizing now is their chance to rescue Ford, a team composed of the twins, Stan, Soos, McGucket, Wendy, Pacifica, and Sheriff Blubs, is ejected out of the Shack-tron, using parachutes to land inside the Fearamid.
Everyone lands right next to the human throne. Mabel travels up the human throne using her grappling hook and finds Ford as a gold statue. Stan yells at her to take Ford and leave, but Dipper says they don’t know how to unfreeze him. Gideon Gleeful, trapped in a cage hanging from the ceiling, says he knows how to unfreeze everyone. He’s dressed up in a sailor costume and explains that Bill forced him to dance for all of eternity as punishment for betraying him. Gideon says that Tyler Cutebiker is the load-bearing statue in the human throne, and if he’s pulled out, the throne will fall apart. When Dipper does so, the throne breaks up and everyone is turned back to normal. In the chaos, Gideon’s cage is knocked to the ground and he’s freed.
Wendy and Pacifica reunite with their families, and Blubs meets up with Deputy Durland. All the citizens are happy to be freed, and Ford is un-petrified as well. He meets McGucket for the first time since he left Ford. McGucket decides to forgive Ford, hugging it out. Stan gruffly greets Ford as well. Dipper and Mabel ask Ford what Bill’s weakness is. He puts on some gloves and asks for something to write with. The only he thing he gets is a blue spray can, but decides it will do. He begins spray-painting a circle on the floor and ends up creating the Zodiac, complete with its ten symbols.
Ford explains that the Wheel is a prophecy. He found a drawing of the Wheel on the wall of a cave many years ago. He recognized some of the symbols then, and recognizes all of them now. It was prophesied that the symbols would create a force that could defeat Bill and reverse his weirdness. Ford dismissed it as superstition at first, but realizes now it’s destiny. Ford tells Dipper to go to the pine tree and Mabel to go to the shooting star. Soos steps onto the question mark and Robbie walks onto the heart. Gideon goes to the pentagram, the sign for the Tent of Telepathy.
Meanwhile, Bill is still fighting the Shack-tron. It manages to pin Bill to the ground, but Bill realizes its legs aren't inside the unicorn barrier. Bill utilizes this weak spot to flip the Shack-tron over, tear off a leg, and smash it into the Shack-tron, sending it flying. Back on the Fearamid, Ford tells everyone in the Wheel to hold hands. When Dipper wonders who the bag of ice represents, Ford explains that some of the symbols are metaphors. The ice is someone cool in the face of danger, causing Wendy to walk onto the symbol after encouragement from her friends. When Ford says the spectacles are someone scholarly, McGucket steps forward. Pacifica walks onto the llama, as her sweater matches it. Ford himself goes to the six-fingered hand. Everyone holds hands, creating a ring of energy that surrounds the Wheel and envelops the Fearamid with dark clouds. All the other citizens rush out of the room.
Ford realizes there’s only one person left to join the Wheel: Stan. Ford yells at Stan to join the wheel, but he remains skeptical. Everyone gets upset at Stan, telling him to join. Stan tells everyone that he isn’t the enemy, and that Ford is for bringing Bill into Gravity Falls. Ford apologises and pleads to Stan one more time. Stan finally agrees, but only if Ford thanks him for spending 30 years bringing him back into this dimension. Ford thanks Stan, getting him to join the Wheel. However, after Ford corrects Stan on his grammar, Stan pushes Ford, breaking the link. The two begin to fight as Mabel and Dipper try to stop them. While they’re distracted, Bill looms above them, having beaten the Shack-tron and regenerated his eye.
Part 2 - Weirdmageddon 4: Somewhere in the Woods
Bill Cipher laughs at the resistance, happy that everyone who could pose a threat to him is in one spot. He sends a wave of fire at them, burning the Wheel away. He also traps Stan and Ford, binding them with ropes. The resistance prepares to fight against Bill, saying they aren’t afraid of him. Stating they should be, Bill snaps his fingers and turns everyone but the Pines into posters showing their screaming faces, to prove himself as a threat not to be taken lightly. Bill then imprisons Dipper and Mabel in a pyramidal cell. Bill says he’ll spare the twins if Ford lets him into his mind, giving him one last opportunity. The twins yell at Ford not to do it, causing Bill to angrily fly up to them. Mabel quickly takes out her spray can and sprays Bill’s eye, distracting him again and freeing Stan and Ford.
While Bill is distracted, Dipper takes out his size-altering flashlight and enlarges the cell, making it so him and Mabel can walk through. Dipper yells at Stan and Ford to run, saying he and Mabel will take care of Bill. When Ford expresses disbelief, Dipper says to trust him. He and Mabel goad Bill into chasing them down a long hallway. As Bill moves to follow them, Stan and Ford try to escape. However, Bill places them inside a larger cell like the one he put the twins in. Bill then changes into a monstrous red and yellow form and chases the kids throughout the Fearamid, threatening to disassemble their molecules. Mabel and Dipper use their grappling hook to escape up a chute, with Bill close behind.
Stan feels guilty for the current situation, feeling that he should have held Ford’s hand in the Zodiac in order to defeat Bill, and that he (Stanley) really is a screw-up. Ford tells Stan not to be so hard on himself, as he made the deal with Bill in the first place. He laments Stan and his’ relationship, wondering how Dipper and Mabel get along so well. Stan says that Dipper and Mabel are kids, so they’re still innocent and that is why Dipper and Mabel are still able to get along so well. Ford decides to let Bill enter his mind, as even if the galaxy is destroyed, there’s a chance Bill will let Dipper and Mabel live. Ford says that if there wasn’t a metal plate in his head, Stan could erase Ford’s mind, killing Bill. Stan wonders what would happen if Bill went in his mind, but Ford says there’s nothing Bill wants in there. Ford remains adamant in his decision, as it’s all they have left.
Meanwhile, Dipper and Mabel run into a dead end. Mabel uses the size-altering flashlight to enlarge her hand, punching a hole through the wall and into the outside. Dipper moves to round up the refugees, but sees that Bill’s henchmen have done that first. While Dipper and Mabel watch, Bill sneaks up behind them and brings them back to Stan and Ford. Bill tells Ford his time’s up, preparing to kill one of the twins. Before Bill does so, Ford surrenders as Stan objects. Bill removes the cell and ties up Stan. Ford’s only condition to the deal is that Bill lets Stan, Dipper and Mabel go. Bill accepts as he shakes hands with Ford. Bill’s physical form turns to stone as his mental form goes inside Ford’s mind.
Ford’s mind is a white landscape with a single wooden door. When Bill opens it, he’s greeted with Stan playing paddleball inside the Mystery Shack. Stan reveals he and Ford swapped clothes and pretended to be each other so that Bill would enter the wrong mind.
In the real world, Ford takes off Stan’s fez and takes out the memory erasing gun, setting it to completely erase Stan’s memory. In the mindscape, Bill tries to call the deal off as the door shuts and the room becomes enveloped in blue fire. Stan explains his mind’s going to be erased with Bill in it. Bill starts to panic and Stan tells him Bill's one big mistake was Bill choosing to mess with his family. Bill tries to escape and resorts to bargaining with Stan, but Stan doesn’t budge. Bill’s form heavily glitches out as he speaks a backwards chant. Stan punches the weakened Bill into shattered pieces as his mindscape becomes consumed by fire, happy he was good for something after all.
In the real world, Ford finishes erasing Stan’s memory. Everyone is freed from the tapestries. Outside the Fearamid, Bill’s henchmen are sucked back into the portal, with the bricks of the Fearamid not far behind. The portal itself closes and explodes into a great shockwave, returning the entirety of Gravity Falls back to its own version of normal. The only thing that remains of Weirdmageddon is Bill’s permanently petrified physical form.
Stan regains consciousness in the forest as Dipper, Mabel, and Ford run to him. Unfortunately, Stan doesn’t remember who any of them are. As Mabel desperately attempts to jog Stan’s memory, Ford sadly explains that Stan sacrificed his memories to save everyone, and that he's their hero. Dipper and Mabel cry as Ford consoles Stan. The four begin to walk towards the now-ruined Mystery Shack. Dipper and Mabel try to remind Stan of the Mystery Shack and themselves, but Stan still doesn’t remember anyone. Dipper wonders if saving the world was worth it if Stan doesn’t remember his friends and family. Mabel tries to find something to bring Stan’s memory back and eventually stumbles across her scrapbook.
Mabel sits down with Stan and begins sharing the stories and memories of her time at Gravity Falls with him. Dipper and Mabel try to frantically remind Stan of the summer, but Stan can’t remember it. As Waddles jumps onto Stan’s lap, Stan involuntarily calls Waddles by his real name, even though he shouldn’t remember it. Ford realizes the scrapbook is working as Stan also calls Soos by his name. Dipper and Mabel continue to show Stan more activities in the summer, showing him all of the things Stan did with them. Everyone begins to laugh, and even Stan joins in as he puts his arms around the twins.
Life in Gravity Falls is back to normal. Shandra shares a news report, expressing happiness that Gravity Falls is back to normal after the events of Weirdmageddon. Some lingering Eye-Bats remain on Sprott’s farm, and zombies pop up in the cemetery as the Valentinos bury them back in their graves. Mayor Tyler gives a speech to the townsfolk to announce the “Never Mind All That” Act, created in response to Weirdmageddon. The act proposes that if anyone asks what happened to Gravity Falls in the past few days, the people must respond with “never mind all that” or risk being tased. Sheriff Blubs and Deputy Durland go mad with power and, it seems, love.
Shandra also reports that the Northwest family has gone broke. After Preston Northwest pledged allegiance to Bill and placed all of his money in “weirdness bonds,” he had to sell the family mansion to preserve his family’s fortune. On the bright side, McGucket regained all of his memory and has made millions of dollars patenting his inventions. He decides to buy Northwest Manor with his newfound money. In addition, Stan has fully regained his memory and is throwing a party to celebrate Dipper and Mabel’s 13th birthday and last day in Gravity Falls. Shandra closes the broadcast with Bodacious T announcing a new sport called "death ball."
At the Mystery Shack, Stan, Ford, Soos, Wendy, Candy Chiu, and Grenda finish singing Happy Birthday to Dipper and Mabel. The entire town has gathered at the Shack to celebrate as well. Mayor Tyler says it’s the least the town could do to thank the Pines for all they’ve done. Gideon says that thanks to the twins, he’ll no longer be evil and will open up his heart. It’s then shown that he tries to be a “normal” kid, but only succeeds in being bullied. Gideon then sics Ghost-Eyes and his other prison buddies on the bullies for revenge.
Soos tells Dipper and Mabel to make a wish. Dipper says that on his first day at the town, Dipper would have wished for adventure, mystery, and friends, but he now realizes he has all of that already. Mabel’s wish would be to shrink everyone down and take them home, but decides on something more feasible: having everyone sign her scrapbook. Mabel swears to never forget anyone in Gravity Falls, and breaks the memory eraser to prove it. Mabel and Dipper then blow out the candles on their birthday cake. Wendy declares the twins to officially be technically teenagers, causing her and her friends to chant enthusiastically.
Pacifica tells Dipper and Mabel to open the presents she gift-wrapped for them. They begin holding up their presents as Ford calls Stan away to talk to him privately. Ford says that he’s beginning to detect strange anomalies in the middle of the Arctic Ocean. He wants to investigate, but doesn’t want to do it alone. He personally asks Stan to come with him and give him a second chance, living the adventures they wished they had when they were younger. Stan agrees to the offer. When Ford wonders what to do with the Mystery Shack, Stan comes up with an idea and whispers it to Ford while Soos eavesdrops in horror.
As Dipper and Mabel look at their presents, Stan prepares an announcement. He says that due to his oncoming adventures with Ford, he'll be closing down the Mystery Shack for good. The town is shocked as Soos runs on stage and speaks against Stan. He feels that the Mystery Shack is a place that fuels people’s dreams and imagination, and if it is shut down, then people’s dreams will be shut down with it. Stan says there isn’t anybody to run the Shack in his absence, but then realizes that Soos would be the perfect replacement. Stan gives Soos his fez, proclaiming that the Mystery Shack is under new management and Abuelita moves in almost immediately.
The time then comes for Dipper and Mabel to go back home where their completely cleared out bedroom is shown (with part of Mabel's headboard ruined presumably due to the destruction caused by Bill) and they are at the bus stop with Stan, Ford, Soos, Wendy, Candy Chiu and Grenda Grendinator. Mabel says it’s time to move on from Gravity Falls, wishing goodbye to Candy and Grenda. Mabel wishes goodbye to Stan as well, happy he’s wearing a goodbye sweater she made for him. Wendy wishes Dipper goodbye as well, telling him that he means a lot to her. She exchanges their hats so they each have something to remember each other by. Wendy also gives him a letter for him to read the next time he misses Gravity Falls.
Finally, the last bus leaving Gravity Falls pulls up to the stop. Mabel realizes she’s said goodbye to everyone except Waddles. Mabel tries leaving him behind, tearfully explaining that her and Dipper's parents probably won't let her keep him as a pet at their home in California. Waddles tries following Mabel, much to her anguish, but Stan (hating to see her so sad) says that if he had to tolerate Waddles all summer, then Mabel and Dipper’s parents now have to as well. He forces Waddles onto the bus and tells the driver that Waddles has to be allowed to ride with the twins. When the driver explains that no animals are allowed on the bus, Stan and Ford flash weapons at him, convincing him to let Waddles on.
Dipper and Mabel hug Stan, saying they’ll miss him. Before stepping onto the bus, Dipper asks Mabel if she feels ready for the unknown, she responds that she doesn't and the twins step on as ready as they could be. As the bus drives away, Dipper and Mabel wave to all their friends, they wave back running with the bus as much as they could. Dipper and Mabel look out the window of the bus. Various creatures wave at the bus after the people as it drives away. Dipper begins a voiceover much like the one he did in the first episode, talking about the mysteries of Gravity Falls. He encourages those who are curious about the town to come visit it and find their own adventure. Mabel falls asleep on the bus almost instantly, indicating that she might not really be so worried about entering the unknown even though she said she doesn't feel ready.
At some point in the future, McGucket officially moves in to Northwest Manor. Soos runs the Mystery Shack with Melody as his assistant. He wears Stan’s old costume and has made a statue of him in his honor, although the scariness of the statue frightens away the children present at the statue's unveiling in the Mystery Shack. Stan and Ford pilot a boat in the ocean, fighting a giant squid. The boat is revealed to be named the 'Stan O’ War II'. Back in the present, Dipper opens the letter Wendy gave him and it reads "see you next summer" signed by all of his and Mabel's friends from the town, Dipper's spirits lift as the bus leaves Gravity Falls and the credits roll.
During the credits, photos are shown of Dipper and Mabel’s various adventures with their friends in Gravity Falls. Some miscellaneous revelations are included, like Dipper clones #3 and #4 from "Double Dipper" are still alive with raincoats and Quentin Trembley from "Irrational Treasure" is still roaming around backwards on a horse. The credits end with a photo of the Mystery Twins and their pig on the bus back in Piedmont, California, by which time Dipper and Waddles had both fallen asleep as well.
After the credits, Bill's petrified stone statue form is shown in live action; isolated deep in a forest, which started the Cipher Hunt.
- Directed by:
- With the Voice Talents of
- Jason Ritter as Dipper
- Kristen Schaal as Mabel
- Alex Hirsch as Grunkle Stan and Soos
- Cecil Baldwin as Tad Strange
- Brian Bloom as Rumble McSkirmish
- Kurt Braunohler as Greg Valentino
- Jackie Buscarino as Pacifica Northwest
- Linda Cardellini as Wendy
- Matt Chapman as Paci-Fire
- Louis C.K. as The Horrifying Sweaty One-Armed Monstrosity (original version)
- Jennifer Coolidge as Lazy Susan
- John DiMaggio as Manly Dan
- Carl Faruolo as Grenda
- Keith Ferguson as Deputy Durland
- Nathan Fillion as Preston Northwest
- Danielle Fishel as Pyronica
- Will Forte as Tyler Cutebiker
- Larry King as Wax Larry King
- Kyle MacLachlan as Bus Driver
- Andy Merrill as Teeth
- T.J. Miller as Robbie Valentino
- Alfred Molina as Multi-Bear
- Kimberly Mooney as Janice Valentino
- Kevin Michael Richardson as Sheriff Blubs
- Stephen Root as Bud Gleeful
- Gregg Turkington as Toby Determined
- J.K. Simmons as Ford
- Thurop Van Orman as Gideon
- Kari Wahlgren as Shandra Jimenez
- Niki Yang as Candy
- Additional Voices
- Matt Chapman - Abuelita and Sev'ral Timez Band Members
- Jackie Buscarino
- Alex Hirsch - Bill Cipher, Old Man McGucket, Gnomes, Sev'ral Timez Band Members, Mayor Befufftlefumpter and The Horrifying Sweaty One-Armed Monstrosity (current version)
- Carl Faruolo - Bully
- Kevin Michael Richardson - Chutzpar
- Kari Wahlgren - Priscilla Northwest
- Niki Yang
- Dee Bradley Baker - Waddles and Sprott (uncredited)
- Casting by:
- Bill's dimension used to be two-dimensional before he "liberated" it. He now seeks to remake Gravity Falls' dimension as he sees fit.
- Bill can haunt people's dreams as he pleases. However, a formal deal is required for him to enter a person's mind.
- All of McGucket's previous inventions that he can remember were originally intended for evil.
- Soos watches a lot of anime and is a fan of gun swords.
- Old Man McGucket does not know what anime is until Soos shows him.
- Paci-Fire has butchered millions on countless moons.
- Bill's eye can regenerate if destroyed, but it takes a few minutes.
- Each symbol on the Zodiac corresponds to a character.
- Most symbols correspond to a physical attribute or article of clothing:
- Dipper is the pine tree, à la his hat.
- Mabel is the shooting star, à la one of her sweaters.
- Robbie is the stitched heart, à la his hoodie.
- Gideon is the pentacle, à la the symbol on his cape and the Tent of Telepathy.
- Soos is the question mark, à la his shirt.
- Pacifica is the llama, à la the sweater she borrows from Mabel.
- Ford is the six-fingered hand, à la his polydactyly.
- Stan is the fish-like symbol, à la his fez.
- The remaining symbols are metaphorical:
- Most symbols correspond to a physical attribute or article of clothing:
- Robbie has had his hoodie since 7th grade.
- Mabel has accidentally sprayed paint in her eyes on multiple occasions.
- Stan and Ford can do perfect vocal impressions of each other.
- Robbie's parents' names are Greg and Janice.
- It is heavily implied that Deputy Durland and Sheriff Blubs share a romantic relationship. However, this is never explicitly stated.
- The Multi-Bear knows Shiatzu massage and took some classes on it.
- Dipper clones #3 and #4 have survived since the events of "Double Dipper" by wearing raincoats.
- Soos has been hugging strangers to practice a moment where hugging is necessary.
- In the beginning of the episode, McGucket is seen using the laptop seen in the first half of Season 2.
- The French Lilliputtian uses the same random French words again.
- Dipper and Mabel mention the previous times they defeated Bill in "Dreamscaperers" and "Sock Opera."
- Bill mentions destroying Time Baby in "Weirdmageddon Part 1."
- The Shack-tron is made up of various objects seen in previous episodes:
- The Mystery Shack makes up the torso.
- The Universe portal is located on the waist.
- The Tyrannosaurus Rex encased in amber from "Land Before Swine" is the left forearm.
- Manly Dan's logging truck is the right forearm.
- The right leg of the Gideon-bot is the right leg.
- Soos' pick-up truck is the left foot.
- The Mystery Shack's totem pole is a shoulder-mounted cannon.
- The head and neck of the Gobblewonker robot are the tail.
- When the Shack-Tron bursts through the Fearamid, Bill says, "What? I just fixed that door!", referring to when Time Baby and the Time Paradox Avoidance Enforcement Squadron broke through his door.
- When controlling the Shack-tron, McGucket uses his beard to operate a stick-shift. He mentioned learning to do this to control his Gobblewonker robot in "The Legend of the Gobblewonker".
- Ford's rescue team also makes use of several items from earlier episodes:
- The Zodiac shown throughout the series is revealed to be a mystical human energy circuit that can generate a force strong enough to defeat Bill.
- Ford mentions the metal plate in his head for the second time, the first being "The Last Mabelcorn."
- Also, in his flashback, the cave painting to summon Bill can be seen in the background when Ford explains his discovery of the zodiac.
- When Bill entered Stan's mind, Stan is shown playing with a paddle ball, which was also played with during the flashback in "A Tale of Two Stans."
- Dipper, Mabel, Ford, and Soos reference the events of "Tourist Trapped," "The Legend of the Gobblewonker," "Summerween," and "Land Before Swine" while trying to revive Stan's memory.
- The events of the week between Weirdmageddon ending and Dipper and Mabel's 13th birthday are mostly skipped over in this episode, but one is later explored in the Gravity Falls: Lost Legends graphic novel story Don't Dimension It.
- Wendy references the events of "The Inconveniencing" when she declares that Dipper and Mabel are now "technically teenagers."
- Blubs and Durland fire the antique cannon from "The Stanchurian Candidate."
- Also, Mabel's red, white and blue sweater can be seen in the end credits.
- Pacifica gets Mabel a mini-golf club and Dipper a Ghost Harassers DVD, referencing her respective encounters with them in "The Golf War" and "Northwest Mansion Mystery."
- Stan and Ford realize their childhood dream of sailing around the world, as mentioned in "A Tale of Two Stans."
- Stan presents Soos with his fez, fulfilling Soos' aspirations seen in "Little Dipper."
- Papers from Dipper's mystery board from the first part of Season 2 appear in the trash can alongside chewed up pens and his love note to Wendy from "Into the Bunker."
- Mabel calls Candy and Grenda her "people" like she did in "Double Dipper."
- Stan and Ford threaten the bus driver with their brass knuckles and ray gun from "Scary-oke" and "Dungeons, Dungeons, and More Dungeons," respectively.
- Stan and Ford sail to the Arctic on the Stan o' War II. The boat is named after the vessel they restored as children in "A Tale of Two Stans."
- Mabel can be seen with gummy worms up her nose during the credits, referencing the short "Mailbox."
- Dipper clones #3 and #4 from "Double Dipper" are shown in the end credits, who have gone into the forest after stealing Robbie's bike, and have survived by wearing raincoats.
- The names of several of Mabel's love interests throughout the series can be seen carved in a tree, including Norman and Gabe.
- Grenda is still dating Marius von Fundshauser after "Northwest Mansion Mystery," and goes to visit him like she had intended in "Dipper and Mabel vs. the Future."
- Quentin Trembley III is seen sitting backwards on a horse on a cliff since his previous disappearance in "Irrational Treasure."
- Stan saying "Seriously do I look like an amnesiac?" from "Roadside Attraction" is a likely foreshadowing to him getting amnesia here after Ford wipes his memories to defeat Bill.
- In its initial airing, this episode was watched by 2.9 million viewers, setting a new record for the network and beating the previous viewership of "A Tale of Two Stans."
- This episode uses a different version of the Weirdmageddon theme song, by using the full-length version of the intro, and with Dipper, Mabel and Stan in their normal roles in the song.
- As of this episode, Jason Ritter is the only actor to appear in every single episode of the series while Dipper and Mabel are the only characters to appear every episode of the series.
- In "Little Dipper", Soos wearing Stan's fez, looking at himself and the mirror and saying "One day" foreshadowed him becoming Stan's replacement.
- The backwards message at the end of the theme song says, "GOODBYE GRAVITY FALLS."
- This episode is the only episode to have flashed two end card pages; one halfway through and one at the end of the episode. This is because it is a special hour-long episode, taking up the length of two episodes.
- It is also the only episode to have two keywords appearing in the background by the key symbol, for much the same reason as the two end cards, this being a double-length episode.
- However, the cryptogram solved by the first keyword is only present in the two-part version of this episode, as the full hour-long version does not have credits between halves.
- After the credits, a split second image of a Bill statue buried in the ground is shown, through a "Blair Witch" style camera filter. This was a clue to the Cipher Hunt.
- Although the subtitles translate the French Lilliputtian's speech, "Je ne sais quoi sacrebleu au revoir!" as "I don't believe that was French," it actually means "Whatever damn Goodbye!"
- This character said this same line in "The Golf War," but the subtitles there translated it as "I don't actually know French."
- Alex Hirsch has said that he teared up while writing the final scene of this episode.
- The only times the phrase "Take Back The Falls" is mentioned in the episode is on a flag outside the Mystery Shack and on the flag that Soos is holding right before the Mystery Shack battle.
- When Mabel reads to Stan from her scrapbook, she suggests that Stan gave her her grappling hook on her and Dipper's second day of Gravity Falls, implying that the events of "Tourist Trapped" took place on the second day as well. However, this is unlikely, given that Dipper mentioned the establishment of a "boring routine" at the beginning of "Tourist Trapped."
- When Gideon is doing cute dances in a cage, the music that plays is Scott Joplin's "The Entertainer."
- During the credits we see a piece of a flannel jacket. This is a piece of Alex Hirsch's jacket that got burned when Gravity Falls got green lit.
- This is one of the few episodes (or at least part of it) to have a definitive date of occurrence, that being August 31, 2012.
- This is the only episode of 2016 which means that the show has lasted nearly 4 years.
- If "Ford" never made a decision to let Bill into his mind, Bill would have killed Mabel as seen on his eye, her symbol.
- When Ford agrees to allow Bill into his mind, his cleft chin is not visible, something notable in almost all shots he is in, while the cleft is seen on Stan instead, foreshadowing that they have switched clothing.
- It is unclear how Stan managed to fake having his brother's six fingers.
- Wendy's letter to Dipper had the signatures of many characters in the show: Stan, Ford, Wendy, Soos, Gideon, Old Man McGucket, Robbie, Pacifica, Grenda, Candy, Nate, Lee, Thompson, Sheriff Blubs, Deputy Durland, Lazy Susan, Tyler, and Schmebulock.
- Lots of things have changed for the characters at the end of the episode:
- Dipper and Mabel go back home to California and take Waddles with them.
- Stan and Ford travel across the sea on their new boat the Stan’o’war II.
- Soos becomes the new owner of the Mystery Shack and runs it with his girlfriend Melody.
- Abuelita moves into the Mystery Shack.
- The Northwest family goes broke and sells their mansion.
- Pacifica gets a job at Greasy's Diner.
- Old Man McGucket buys and moves into the Northwest Mansion and reconciles with his son Tate.
- Li'l Gideon decides to open up his heart and become more positive and friendlier towards people.
- Grenda and Candy visit Marius in Austria.
- Sheriff Blubs and Deputy Durland confess their love for each other.
- Mayor Tyler passes the "never mind all that" act so no one would know about the events of Weirdmageddon.
- During the credits there are a lot of scenes featuring the characters doing stuff:
- A bubble popping on Waddles' snout.
- A dandelion and Mabel winking.
- Mabel painting a turkey on Ford's hand.
- Dipper and Mabel holding sparklers with Mabel having gummy worms up her nose.
- Old Man McGucket relaxing in a pool along with his son Tate and his raccoon wife.
- Mabel letting Stan try out her grappling hook with Ford.
- Quinten Trembley staring at the sun on the back of a horse.
- Dipper Clones 3 and 4 living in the forest with raincoats on.
- Mabel, Grenda, and Candy taking pictures of themselves in a photo booth.
- Some Mystery Shack stuff by a window.
- Dipper, Mabel, Stan, Ford, and Soos watching a scary movie and then falling asleep.
- A tree featuring heart carvings of Mabel's ex-crushes crossed out, leaving one with just herself on it.
- Some ice cream treats.
- Candy and Grenda on Marius' yacht with Grenda kissing Marius.
- Wendy laughing and making a silly face.
- Mabel pretending to eat the sun.
- Dipper and Mabel asleep on the bus arriving back home to Piedmont.
- This episode premiered on Presidents Day.
- In Gravity Falls: Journal 3, its revealed that the Journals were restored after the events of Weirdmaggedon were undone are were later discovered by Soos and given to Dipper. After keeping them to himself for a few days Dipper gave them to Ford and the whole Pines family decided to throw them into the Bottomless Pit after all the trouble they caused them. Journal 3 was then discovered by troopers of the Parks Department in Oregon which gave them headaches and nightmares, then they put it up for sale at their Confiscated Items Sale/Bake-Off.
- It could be determined that the Journal fell into our world or one where Gravity Falls doesn't exist.
- Originally there was plans for an epilogue episode to follow up after the events of Weirdmageddon. The episode would follow Dipper and Mabel packing and reminiscing about their time in Gravity Falls. Blendin would then appear and warn them about time anomaly bubbles still floating around the town. Eventually the twins somehow fall into one and are transported to the first day they arrived in Gravity Falls (before the events of Tourist Trapped). They see how much they were not excited about being there and see how far they had come in their development. The idea was eventually not used and Blendin's fate would end up being different as well as the twins' final days in the town. 
- During MomoCon 2017, Alex Hirsch revealed during a guest video chat appearance that Disney originally wanted to cut the song We'll Meet Again out of the episode due to how much it was costing to get the rights to use it. He would keep sending them emails with just the word "Please" and "Yeah" to get them to reconsider until they finally were worn down and responded with, "alright we’ll spend thousands of dollars."
- Emmy Cicierega created a semi live-action/stop motion opening for the executive pitch of Weirdmageddon 3. She later uplaoded it to YouTube with an instrumental version of "When He Died" by Lemon Demon playing in the background. 
- The name of the episode given during this pitching was Twindependence Day, a play on the name of the 1996 American science fiction action film Independence Day.
- The box set revealed a few deleted and cut scenes from the episode:
- Gorney is seen asking Stan if someone can get his parents back as he's very lonely.
- Pacifica is shown to also be missing her parents but also heartbroken that her mansion is half destroyed and she has no money anymore.
- Blubs is shown to be the most heartbroken, expressing how much he misses Durland under a spotlight while wearing a T-Shirt with his face and the phrase "Save Durland," on it.
- A butler inside Northwest Manor is seen hiding and watching as the Shacktron makes its march towards the Fearamid.
- Cthulhu is seen guarding the Fearamid and talking about his hopes to one day make it into Bill's inner circle and be something beyond a guard.
- Cthulhu is again seen about to eat a child hiding in a destroyed car when the Shacktron punches him using Greasy's Diner, knocking him into a pillow store.
- Emmy Cicierega also was responsible for all the polaroid animations that played during the end credits. According to her, she was was tasked with coming up with some cute and happy scenes for the end credits. It also helped her feel way less sad about the show ending. Some of them were also done by Alex.
- In October 2016, Emmy uploaded a video montage of all the cut scenes to her YouTube channel, with help from Alora Lanzilotta for editing the boards into video and doing scene timing in order to make them all viewable. the song Kubrick And The Beast by Lemon Demon is played as a background song.
- In all, the prompts that did not make it into the end credits were:
- Dipper, Mabel and Soos playing in the mud during the rain as an unamused Stan watches and gets soaked in some when they jump into a puddle.
- Dipper, Mabel and Soos getting marker tattoos from Wendy and the bouncer from the bar in Headhunters giving them a thumbs up.
- Mabel learning McGucket's dance moves.
- Dipper playing the Sousaphone for Wendy and Mabel who are pretending to look happy about it.
- Mabel applying black nail polish on Robbie's finger nails.
- Dipper, Mabel and Wendy race down a hill in a shopping cart, while being chased by Blubs and Durland in another shopping cart.
- In an alternate take of Grenda on Marius von Fundshauser's yacht, we see Wendy, Mabel, Candy and Dipper there with them too. Everyone is having fun except for Dipper who appears to be sea sick.
- In the bit where McGucket is swimming in the pool with his Raccoon wife, his son is not originally in it and it is a much closer shot.
- Both Stan and Ford try to give an old lady on a bench a flower. She isn't amused by it and leaves. Stan and Ford then start arguing about it.
- Soos and Dipper wear the Pterodactyl Bros shirts while setting up a display or Pterodactyl merchandise in the gift shop.
- While fishing with Stan on a bridge over a river, Mabel catches one of the Several Timez members swimming in it.
- Dipper braids Mabel's hair in an awkward way which Mabel finds amusing.
- While spinning Dipper around on a tire swing, Mabel falls and his hat lands on her head backwards. She is fine.
- In a different take to Trembley's appearance, he is saluting in front of an American flag. The flag turns out to be in a post office, where an employee chases him out with a broom.
- A dandelion is seen having its seeds be blown away by the wind, likely to show that the summer was ending.
- A hand is seen taking ice cream out of the Mystery Shack gift shop freezer.
- Instead of Mabel, the person who would originally pose to appear to be eating the sun at sunset is Stan.
- The fortune telling machine gives a person a fortune with the message "Duck." They then appear to duck.
- Dipper is skipping stones along the lake and is able to skip one 4 times. He then turns around to look at the camera to show excitement over it. At that moment, the real Gobblewonker surfaces with the stone sitting on top of its head.
- A Jack-o'-melon from Summerween is seen glowing on a picnic table with pieces of it on a plate in front of it.
- Instead of gummy worms, Mabel was originally supposed to have sparklers up her nose.
- Dipper, Mabel and Soos are dancing in the living room while Soos is playing a keyboard on the couch. The scene pans over to show 3 gnomes stacked on top of each other, dancing to the song too.
- In a final post credits scene, Mabel is seen showing her scrapbook to students in her new class at the start of the school year. She exclaims that all the the polaroid shots we see are what she did during the summer with Dipper. Waddles then pops out of Mabel's bag, at which point the teacher facepalms.
- When the channel were showing commercials for the finale, one of them was the flag that appears later on in part 2 of this episode (Weirdmageddon 4: In The Wood on other channels around the world), and the background of the ruins of the town from the Weirdmageddon remixed theme song.
- Bill's hat isn't on his head when entering Ford.
- Alex Hirsch stated in an interview that he imagined Pacifica getting a side job at Greasy's Diner working with Lazy Susan after her family lost Northwest Manor.
- In the Shmeb-you-unlocked page, the vigenère code on the side says, "Got a waitress job at Greasy's diner after the summer ended. Thinks about the Pines twins every day."
- During the ending credits of the first half of the episode, there is a cryptogram that reads "KVOU VTKSE XVREOW DQTMJKGD MF KNLJH CVE 900 YCHJZ OH XXFB PJPSKC FVQUSIOV LHP: FRNLLCDBFBF." Using the vigenère cipher, it translates to "SOOS LATER FORCED MCGUCKET TO WATCH ALL 900 HOURS OF NEON CRISIS MECHABOT BOY: REVELATIONS."
- Keyword: SHACKTRON, letters spread among the cans of The Brown Meat behind Stan.
- This cryptogram is not present in the full hour-long version of the episode.
- The page section revealed at the end of the first half of the episode says, "4-19-10 [] 8-12-23-21-19-20 [23|23-6-9-3-10-20 23] []. [15-10|16-23-10-20 15-10] 16-23-10-20 4-16-19-25'[22-9-10-20|12-12 22-9-10-20] [5-19-23-12|4-16-19 5-19-23-12]. [22-6-19-23-13|22-3-4 22-6-19-23-13] [21-16-23-15-10|4-16-19 21-16-23-15-10], [8-23-25|23-10-20 8-23-25] [21-9-5-4|4-16-19 21-9-5-4]. 4-16-19 8-6-9-8-16-19-21-25 [23-12-12|1-15-12-12 23-12-12] [12-9-5-4|22-19 12-9-5-4]." Once decoded using the combined cipher it reads, "TEN SYMBOLS PLACED AROUND A WHEEL. HAND IN HAND THEY'LL BOND THE SEAL. BUT BREAK THE CHAIN, AND PAY THE COST. THE PROPHECY WILL ALL BE LOST."
- There is a code on the bus seat that reads "ZMFUIGV PSHP IGK AGTAYAG TRMNE VVGSQW KLE JOJXU GIMWZ." Once decoded using the vigenère cipher it reads "SECRETS LOST AND STATUES FOUND BEYOND THE RUSTY GATES".
- During the ending credits of the second half of the episode, there is a cryptogram that reads "GLCOPRP GOOGWMJ FXZWG." Using the vigenère cipher, it translates to "GOODBYE GRAVITY FALLS."
- Keyword: AXOLOTL, can be seen on the door frame leading to the living room as the Pines lead Stan into the ruined shack after Bill's defeat.
- The page section revealed at the end of the second half of the episode says, "[] [] 22-12-19-23-21-16-19-20 [5-3-10|22-25 5-3-10]. [4-23-12-19|4-16-19 4-23-12-19]'5 4-9-12-20, [5-3-11-11-19-6|4-16-19 5-3-11-11-19-6]'[20-9-10-19|5 20-9-10-19]. 15-10 [] [8-15-10-19-5|4-16-19 8-15-10-19-5] 5-4-15-12-12 8-12-23-25. [23 5-3-10-10-25|9-10 23 5-3-10-10-25] 5-3-11-11-19-6'5 20-23-25." Once decoded using the combined cipher it reads, "FADED PICTURES BLEACHED BY SUN. THE TALE’S TOLD, THE SUMMER’S DONE. IN MEMORIES THE PINES STILL PLAY. ON A SUNNY SUMMER’S DAY."
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