Shared Pixar universe

The shared Pixar universe is a theoretical shared universe incorporating all of Pixar's feature films, including Inside Out. If the theory is true, given Riley Andersen's appearances in Downfall parodies, the universe would also be the same as the Downfall parody universe, incorporating many "based on a true story" war movies and their parodies, as well as the American Girl movies and their parodies.

The universe, in a couple of different forms (sometimes including all the movies John Lasseter is involved in, as seen on, for example, this Hitler parody), has been proposed since at least 2003; however, in its current form, it only gained ground with Jon Negroni's 2013 blog post and subsequent book The Pixar Theory. Negroni's theory has been further developed by the YouTube theorists SuperCarlinBrothers and Seamus Gorman, updating for movies released since the original blog post and book were published, including Inside Out. However, other theorists have discredited Negroni's theory entirely and are looking forward to developing their own, sometimes with adjusted rules as to what constitutes a single universe.

So far, the theoretical universe has been denied by Pixar's higher-ups, who claim that the movies were never intended to be connected and that the apparent connections are simply coincidences. However, Pixar's YouTube channel did once refer to "the Pixar film universe", albeit only as the narration, not as an official with any capacity to proclaim the theory as canonical.

Proposals
Any proposal for the shared Pixar universe, by definition, must include all of Pixar's feature films. However, given this, it also must include shorts set in the films' universes, such as Riley's First Date?, and Planes by DisneyToon Studios, said to take place in the Cars universe.

Jon Negroni
Negroni's proposal mostly involves a single universe in which every event of every Pixar movie can be placed. While this approach has worked with both Monsters, Inc. with the insistence that doors are actually time machines and Cars with the insistence that it's a post-apocalyptic world, it quickly falls apart with the universes of both Inside Out and Coco, which are much more expansive than the Earth can ever be.

The point of divergence of Negroni's Pixar universe from our universe is 65 million BCE, with the Chicxulub meteor narrowly missing the Earth. This means that dinosaurs did not go extinct at that point in time, facilitating their appearance alongside cavemen in The Good Dinosaur; however, it's theorized that the dinosaurs went extinct due to other reasons, but nevertheless altered the path of evolution, providing some species of animals appearing in Pixar movies that have no real life counterparts, such as Kevin's species in Up.

Movies placed in the modern times in the theory suggest three distinct "races" fighting for the dominance of the Earth: humans, containing a lot of potent energy in form of both emotions (as seen in Inside Out) and memories (as in Inside Out and Coco), animals, who subsist on said energy and are malicious towards humans (as in Finding Nemo and Ratatouille), and inanimate objects, who are made animate by said energy and realize their connection with humans (as in Toy Story). Said energy can also grant humans extraneous powers, creating Supers, as seen in The Incredibles. Human-animal hybrids, as well as humans who can transform into animals, also exist, as seen in both Luca and Turning Red.

Eventually, humans and animals go to a war, which the humans, with robots on their side and unified by Buy-N-Large (suggested to be a company ruled by an AI which is the direct descendant of the AI created by Syndrome during the course of The Incredibles), win, but at the cost of abandoning their planet, as seen in WALL-E. Before the humans return, though, cars, qualifying as inanimate objects, briefly dominate the Earth, as seen in Cars.

However, after humans return, the growing separation between them and animals, as seen in A Bug's Life, leads to another war, which the animals, now mutated due to the Earth's radiation, win, eradicating humans. These animals become known as monsters, as seen in Monsters University and Monsters, Inc., and, like their predecessors, subsist on human energy, harvesting it via time travel doors in form of screams, as seen in the movies, as well as laughs, as seen in the companion series Monsters at Work. However, as Boo from Monsters, Inc. learns about the monster world/time, she masters time travel via doors on her own, landing her in the time of Brave, where she becomes the Witch, connecting the first (before The Good Dinosaur was released) and the last movies of the universe in a stable time loop, as well as giving Boo the opportunity to place Easter eggs not normally explained by the theory.

Onward has been a significant hurdle to overcome for adherents to the Negroni version of the Pixar universe, as it is explicitly set on a planet that has two moons and its own self-contained history as a magical world that gradually developed technology and became mundane. However, some have proposed that it is a planet somewhere else in the Pixar universe, unsatisfying as the idea is (as it wouldn't connect Onward to any other Pixar movie), while others suggested that the story is an in-universe one, conceived by Andy Davis, the main human character of Toy Story through Toy Story 3. Soul is another movie that's difficult to fit in the theory, as it explicitly describes a form of afterlife contradicting that of Coco.

Pixarverse theory
Members of the Discord servers CreativityTheEmotion has been involved with, such as Pizza Planet, informally led by a rivaling server's leader, have begun putting forward and developing their own Pixar universe theory, completely discrediting anything Negroni might have said; to distinguish the theory from Negroni's "Pixar theory", it has been given the name "Pixarverse theory". Unlike Negroni's theory, the Pixarverse theory does not object to placement of Monsters, Inc. and Cars in their own universes, rather than the same universe which uses different calendars to keep a "modern" feel to each series, and even gives each separate universe, or "dimension", names: Dimension A113 for the majority of Pixar, Dimension M1 for Monsters, Inc. and Dimension CD for Cars. The number of dimensions in this theory is not exhaustive, meaning that Onward could be integrated as a dimension separate from A113, M1 and CD.

Other
Matthew "MatPat" Patrick of the channels The Game Theorists, The Film Theorists and The Food Theorists has begun a series on Pixar movies, in which he attempts to piece his own Pixar universe theory. Among his conclusions are:


 * Cars and A Bug's Life both take place in the distant future, with bugs becoming a dominant species and evolving into cars, hinted by the cars' coating being similar to the bugs' exoskeletons and some cars having bug-like wings, rather than airplane-like ones.
 * The Toy Story series is eventually poised for a war between toys and humans, which the toys are bound to win due to possessing immense biological advantages over humans, such as virtual immortality/indestructibility and their secret code which leads to humans not even being aware that toys are alive.
 * In WALL-E, throughout the lifetime of the Axiom, meat of dead humans has become the primary form of subsistence.

Connections of Inside Out
The following details connect Inside Out to other Pixar movies:

Recurrent gags of Pixar films

 * A113: is seen as grafitti as Riley runs away (Onset of Depression for Sadness). It is also purported to be the number of Riley's classroom (Breakdown at Class), but the classroom door is never actually seen from the outside.
 * Pizza Planet truck: appears throughout the film as one of Riley's memories. It has been said that there are three occurrences of the truck in the entire film, and a tongue-in-cheek prize of $50 was suggested for someone who can find them all. The appearances are:
 * Meeting Bing Bong: a memory of the truck is dropped by Bing Bong as he first notices Joy and can be seen in the foreground once she starts chasing him.
 * Hockey Tryouts: a memory of the truck is mixed in with other happy memories, which Fear purports are of hockey and are to substitute for the Core Memory powering Hockey Island.
 * Discussion on the Train: a memory of the truck is near Bing Bong's trunk as he picks up the twisty tree memory.
 * Luxo ball/Pixar ball: appears in a memory of Riley's childhood, as she's playing with Bing Bong (Reminiscing Riley and Bing Bong).
 * John Ratzenberger, Pixar's "lucky charm" with an appearance in every movie up to Onward, voices Fritz, the Mind Worker in charge of installing Riley's new console (Upgrades).

Other cameos in Inside Out

 * Throughout the film: In addition to the Pizza Planet truck, Riley's memories feature Carl and Ellie's wedding and the subsequent "Married Life" scene from Up.
 * Riley's Memories and Islands of Personality:
 * In the first memory that Joy picks up and hugs, the playground is taken from Sunnyside Daycare in Toy Story 3, albeit with changes.
 * A picture of Ellie from Up can be seen in the Core Memory associated with Goofball Island.
 * Riley's Life Montage:
 * A magazine featuring Colette from Ratatouille on the front page can be seen.
 * As Riley goes to sleep, the stars from the Buzz Lightyear aisle in Toy Story 2 are reused for her bedroom stars. They reappear in Riley's daydream further on.
 * The Big Move:
 * The cars in San Francisco have bumper stickers from Cars.
 * Models from Cars 2 are reused as background cars.
 * The New House: The dead mouse resembles Remy from Ratatouille.
 * The Time Outside: The statues in Riley's memory of "that time with the dinosaur" are based on The Good Dinosaur (upcoming as of the release of Inside Out).
 * Joy vs. Dream Productions:
 * The bear bringing pizza resembles Queen Elinor from Brave in bear form.
 * The pizza itself has arms identical to those of Mr. Potato Head from Toy Story.
 * Breakdown at Class:
 * The globe from all three Toy Story movies can be seen in the background. The same globe also appears in the background of the teacher's mind as a giant prop.
 * One of the students in Riley's class is wearing a camouflage made up of Toy Story characters, while another is wearing a skull shirt reminiscent of that of Sid's, also from Toy Story.
 * Dinner Table Scene: Riley and her family eat from Chinese food boxes first appearing in A Bug's Life and reoccurring in many other Pixar movies, including Toy Story 2, Monsters, Inc., Ratatouille and Incredibles 2.
 * The Journey: When Bing Bong empties his bag, one of the items is the boot containing Earth's last plant from WALL-E.
 * A Mayoral Tour: Riley's Imagination Land features board games themed after both The Good Dinosaur ("Dinosaur World") and Finding Nemo ("Find Me!"). Both are possible references to upcoming movies, as The Good Dinosaur and Finding Dory, the sequel to Finding Nemo, followed Inside Out.
 * Hockey Tryouts: In the background, a banner reading "Tri-County Youth Hockey" can be seen, a reference to Toy Story taking place in the Tri-County Area.
 * Riley's Nightmare: The giant legs of Ted from Monsters, Inc. appear as background props.

In other films

 * Despite the tradition of Pixar movies including a cameo for the next movie in line, no such cameos exist in movies prior to Inside Out, due to The Good Dinosaur being thought to be the next movie in line as of the release of Monsters University.
 * Finding Dory: Riley and many of her classmates appear as cameos. Similar, yet distinctly younger, models of the same people also appear as cameos in Sunnyside Daycare in Toy Story 3.
 * Cars 3: TripleDent Gum is a sponsor of Terry Kargas and Cam Spinner. This is the first of many appearances that establish TripleDent Gum, alongside Dinoco and Buy-N-Large, as one of the fictitious companies appearing as cameos in Pixar movies.
 * Incredibles 2: A TripleDent Gum advertisement appears on a billboard from a building during the train chase when Elastigirl crashes through a window of a building.
 * Toy Story 4: A vintage TripleDent Gum poster can be found inside the antique store.
 * Onward: TripleDent Gum is sold in the gas station's mini-mart.
 * Soul:
 * The princess castle from Imagination Land appears in the Hall of Everything.
 * Bill Andersen's startup, Brang, is advertised in the subway.
 * Luca: Nick Pitera, the singer of the TripleDent Gum jingle in real life, is referenced as "Nicolò Pitera", one of the artists whose records Giulia owns.

Common voice actors

 * Bill Hader, playing Fear, previously played the Slug Monster Student in Monsters University, and goes on to play Axel the Carnie in Toy Story 4.
 * Richard Kind, playing Bing Bong, previously played Molt in A Bug's Life, Van in Cars and Cars 2 and Bookworm in Toy Story 3.
 * Frank Oz, playing Subconscious Guard Dave, previously played Jeff Fungus in Monsters, Inc..
 * Lori Alan, playing Jill Andersen's Sadness, previously played Mrs. Anderson, Bonnie Anderson's mother, in Toy Story 3, and reprises the role in Toy Story 4.
 * The clips of Boo in Monsters, Inc., played by Mary Gibbs, were reused for young Riley's screams and cries.
 * Pete Docter, the director of Inside Out who played Bill's Anger, has roles in all movies which he has directing credit of, as well as other Pixar features, including unspecified additional voices in Monsters, Inc. and The Incredibles, the Lifeguard Bot in WALL-E and Campmaster Strauch in Up.

Placement of Inside Out
Disregarding the spiritual connection of Inside Out and the importance of both emotions and memories to the Pixar universe, there are two rivaling and inconsistent placements of the film in the universe. Jon Negroni, the original theory proponent, originally preferred 2015, the year the movie was released, due to the technology we see throughout the movie — like a Skype surrogate that closely resembles the one used by Trixie in Toy Story 3 and the presence of smartphones. However, others have made the argument for the 2000s, to consistently place the Ratatouille and Finding Dory connections, even though this would be contradicted by the technology, and Negroni can be seen to acknowledge this in an episode of Jon in Theory. That being said, both dates are disregarded by CreativityTheEmotion, who, based on chat nicknames in the Riley Andersen vs. Meg scene, believes Inside Out to take place between January 2011 and January 2014.

Shared Pixar/parody universe
Andersen's Mind, as a series, was not intended to take place in the Downfall parody universe, rather creating its own universe. However, crossovers by JJ All-star featuring Riley alongside parody characters suggest that Inside Out, and therefore, per Negroni, the rest of Pixar is part of the parody universe. Another connection between Pixar movies and Downfall parodies is that of Professor Zündapp from Cars 2 and Hermann Fegelein from Downfall, both portrayed by Thomas Kretschmann and therefore connected per parody logic.

If the two shared universes are connected, the shared concepts of each universe, such as "Will o' the Wisps" giving animals and inanimate objects human-like intelligence in Brave and the antic powers in the parodies, would have to be integrated. In addition, the timelines would have to be integrated.