Boo — pixar

Sulley: Mike, this isn't Boo's door!
Mike: "Boo"? What's "Boo"?
Sulley: That's... what I decided to call her. Is there a problem?
Mike: Sulley, you're not supposed to name it. Once you name it, you start getting attached to it! Now put that thing back where it came from, or so help me...!

—Mike and Sulley

Boo is a toddler who accidentally gets into the monster world in Monsters, Inc.

Monsters, Inc.

First meeting

"Boo!"

—Boo

Boo is a 2-year-old human toddler and among many of Randall's potential victims as part of the CEO's plan to forcibly extract screams in order to answer the energy crisis. However, the plan goes awry when Sulley returns to Scare Floor F on Mike's behalf to retrieve his documents while the latter is dating Mae so they can be turned in to Roz later. Sulley happens to spot Boo's Room near the documents and opens it out of curiosity, causing Boo to escape and horrifying Sulley, who, as with many monsters, assume human children can poison them on contact. Sulley's attempts to return Boo fail as she repeatedly catches up to him, and he eventually hides Boo in a handbag before returning to Mike. Randall notices Boo's disappearance, but not Sulley's involvement, and brushes it off as Sulley leaves. Boo ends up freeing herself from the handbag without Sulley watching and causes panic at Harryhausen's, with the two barely escaping as the CDA quarantine it with a force field. The pair were forced to hide Boo in their residence and continue to avoid her for their own safety, but this results in Boo crying instead until Sulley appeases her. Mike then inadvertently gets stuck in a trash can and amuses Boo, generating enough energy to cause a temporary blackout. After brainstorming plans to return Boo without detection, they decide to fashion a monster costume for her out of Sulley's sofa.

Returning Boo home

Attempting to return Boo home becomes increasingly difficult for Sully and Mike due to their shift, not to mention that Randall is aware she is with Mike. After learning that Mike made a deal with Randall to return Boo home, she is unwilling to go back to her room, as she is scared of Randall. This also makes Sulley suspicious and he refuses to trust Randall, so Mike (thinking that Sulley is being delusional) tries to prove them that there's nothing to worry about. Sulley's suspicions are ultimately proven correct as Randall ends up capturing Mike, as he was hiding in the room waiting to capture Boo, but Sulley eventually rescues him. At one point, Sulley, under Mr. Waternoose's orders, then roars like a lion in front of a child used for simulation, not noticing that he has also scared Boo. Sulley tries to apologize to Boo, but she is too terrified of him and runs to cower underneath Waternoose's legs. Waternoose, who has caught sight of Boo, decides to take care of her before anything worse happens, but Mike and Sulley are unaware that he is actually working with Randall. After he and Randall banish them to the Himalayas to keep them from interfering with their plans, they proceed with extracting screams from Boo by using the Scream Extractor. However, Sulley (who managed to find his way back to the monster world) arrives at the last moment to disable the device to free Boo.

Mike catches up with them, and they rush back to Scare Floor F, with Randall in hot pursuit. Randall chases them to a large chamber where thousands of doors to human world are kept. Mike and Sulley then make Boo laugh to activate the doors, then they go through them, exiting the monster world and entering back into it, in order to lose Randall and reach Boo's door. Just as it looks like Mike and Sulley have lost Randall, Boo suddenly slips off from Sulley's arms, and Randall reveals that he has caught her and drops the door that the two are holding onto (although they managed to enter the door before it is destroyed, as Randall forgot that their door was still activated).

Sulley manages to catch up with Boo, but then Randall ambushes Sulley. Just as Randall is about to finish Sulley off, Boo snaps and suddenly jumps on Randall, beating him with a baseball bat and disrupting his camouflage, allowing Sulley to restrain Randall. Mike and Sulley then dispose of him by throwing him through a door before destroying it, leaving him at the mercy of some rednecks as Boo blows a raspberry.

Mike and Sulley open Boo's door, only to realize that the power has went out. Mike was not able to amuse her to power it back on before Waternoose activates the door transit and brings it to Scare Floor F, where he and the CDA are waiting. Mike runs off with Boo's monster and distracts the CDA, but Waternoose notices Sulley with Boo and her door before giving chase. Sulley sets down Boo in the simulation room just as Waternoose barges in, and, after a brief argument regarding the CEO's child abduction scheme, is thrown aside. However, Waternoose ends up grabbing the dummy as Boo already crawled away. Mike, who presumably convinced the CDA to hear him out, terminates the simulation, lifts the surrounding barriers and replays the live confession. Boo emerges behind the bed, but Sulley ushers her away.

After Waternoose is arrested and Roz reveals herself as CDA Agent 001, Sulley requests to send Boo home. Roz agrees and gives them five minutes before the CDA shreds the door so they can cover up the incident and avoid panic. Sulley takes her in to her room and tucks her in after she shows him her toys, including Jessie the Yodeling Cowgirl from Toy Story 2, a ball from Luxo Jr., and Nemo from Finding Nemo.

Boo and Sulley take a possibly one last look at each other, then after Sulley closes the door, Boo then opens it to possibly surprise him, only to find her closet instead and Sulley nowhere. Sulley is visibly dismayed at the thought of never seeing Boo again, but manages to discreetly retrieve a splinter on the ground.

With Waternoose out of the picture, Sulley and Mike are promoted in his place. One of Mike's remarks on Waternoose reminds Sulley of power surges caused by Boo's laughter, inspiring him to retool Monsters Inc. scarers into comedians. Mike managed to discreetly retrieve the remains of Boo's door and reassembles it. Sulley installs the last fragment to activate the door, and presumably finds Boo still waiting for him on the other end, much to his relief.

Personality

Boo is a nauseatingly adorable toddler who is curious, and naive. She can speak, but has baby, gibberish vocabulary. The only actual words she says in the film are "Boo!", "Kitty!", "Ew" and "Mike Wazowski!". In other ways, she is advanced for her age, such as already being potty trained. This is seen when she shows to Sulley that she needs to go to the bathroom and doesn't need help.

Appearance

Boo has brown eyes as well as brown hair in pigtails with pink hair ties. She is shown wearing a pink nightshirt, purple capris leggings, and white socks. She makes friends with Mike Wazowski and Sulley after she sneaks through her door into Monsters, Inc.

Trivia

In one of the film's early drafts, she was originally an 8 year-old boy named Raymond, who befriended Sulley (back then named Hob).
According to the artwork in the DVD, there are a bunch of drawings of Boo being slightly older (possibly around the ages 5-10) in her early works; but the final designs were later confirmed that Boo would be a toddler instead of a child. In the documentary with the characters, Billy Crystal said that Boo was an adorable three-year-old little creation.
At another point, Boo was going to be the youngest and only girl out of ten siblings, with the others being boys, who was contastantly picked on by her brothers and befriended Sulley (then known as Johnson) so that he could protect her.
In Cars, a car version of her named "Boomobile" is mentioned.
In her bedroom, Boo has a Pixar Ball, a rubber Nemo squeak toy (Finding Nemo had not even been released yet at the time), and a Jessie doll.
In an early animation test for Boo's T-shirt, it has a picture of Heimlich from A Bug's Life on it.
During the scene where Sulley and Mike hide Boo in the bathroom, one of the songs Boo sings behind the stalls is "Beauty and the Beast" from the animated Disney film of the same name.
In a book based on the first film, it is revealed that Boo's real name is Mary Gibbs (the same name as her voice actress). In the film, she signs her drawings with the name "Mary".
According to some Monsters, Inc. coloring pages, some of the outfits Sulley and Mike made Boo wear before deciding on the monster costume was that of a princess, a witch, a clown, and a doctor.
When Boo tries to open her closet door after Sulley tells her goodbye and closes it, she is now 7% taller since the programmers noticed that she was too short.
Mary Gibbs was only two-and-a-half years old when she voiced Boo. Because she was so young, it proved difficult to get her to stand in the recording studio and do her lines. Instead, they simply followed her around with a microphone to record her dialogue.
Originally, Boo was going to return in Circle 7's Monsters, Inc. 2 as a teenager. In this film, Sulley and Mike, while trying to celebrate her birthday, find out that Boo and her family have already moved to a different house when they find an old woman sleeping in what was once her room one day, causing the two monsters to travel into the human world to look for her new house. Unfortunately, the two monsters start to forget how to get back to their world, and to make matters worse, Boo doesn't even remember them anymore since teens and adults do not believe in monsters, nor does she think they're funny, and the only way to get back is to try to make her laugh again. The reason why this sequel was scrapped in the first place was because John Lasseter thought that the final shot of the first was just too heartwarming to be continued.^[1]
Some of Boo's cries and squeals are reused in Inside Out for a younger Riley. In fact, the credits list Mary Gibbs as an additional voice because of this.
Boo has not made any appearances in the series Monsters At Work, as it is set before the epilogue of the original movie. However, she is mentioned in two episodes of season 1: "The Damaged Room" and "It's Laughter They're After".^[2]