Why do they still think Boo is toxic?
- When Boo is in their apartment, Sulley and Mike avoid touching her with bare hands as they think she is toxic. However, when Sulley first meets Boo she was lifting and dropping his tail, so surely that proved that she wasn't?
- Just because arsenic does not instantly kill you when you touch it does not mean you want to keep touching it. Also, since children are such a huge unknown save to the CDA, it may be that while they know kids are dangerous, they may not know how they are dangerous. For all we know, Sulley had spent hours wondering if his tail was gonna fall off, and only concluded she wasn't when that didn't happen.
What happens if you're inside the closet when the portal opens?
- Two possibilities:
- One, it's impossible to connect to a closet door if someone's inside.
- Two, you get sent to the monster world and it's in fact how Boo got there: she was hiding in the closet trying to avoid Randall.
If the doors need power to operate but provide the power for the monster world, then how did they start working in the first place?
- All There in the Manual. Monsters used to travel to human lands by conventional means to gather screams, but this was dangerous, so the Waternoose family innovated a safer way (though it does raise questions of which way one is supposed to travel).
In the monster world, what happens if you open the door from the other side?
- Most doors can only open in one direction - toward their hinges - so that's probably impossible. Either that, or you end up inside the closet.
If Boo is revealed to be scared of Sulley, why didn't he just scare her off earlier?
- She was not "revealed to be scared". From Monsters University, Dean Hardscrabble pointed out to a once arrogant Sulley that children have specific fears that make them scared; any other means of trying to frighten them will only make them upset. Boo felt betrayed and upset when he roared in front of her; what she thought was a big cuddly teddy bear suddenly turning into a huge-fanged beast. Also, as scared as he was of her, he didn't just want to abandon her in a hostile environment.
Who really believes that children are toxic?Mr. Waternoose was the head of the conspiracy to capture kids, so he must know they are ok. Meanwhile, Roz, the head of the Child Detection Agency, also seems to know that kids aren't toxic, in which case what's the point of the CDA?
- Partly so the monsters would be more privy to the idea of terrifying children (the monsters aren't evil by nature, after all) and partly because while kids aren't poisonous, they are dangerous. Boo laughing causes a power surge. If Waternoose's plan had gone through there would likely be an uproar and the monster would might be discovered by humans.
- In which case, why are the CDA so vigilant? They really *seem* to think the kids are toxic.
- They may actually believe it. They are just the foot soldiers. Either that, or they're acting, for the sake of holding up the pretense.
- In which case, why are the CDA so vigilant? They really *seem* to think the kids are toxic.
- The CDA exists because, because they mess with the power grid. The whole "poison" thing is probably just a scare tactic to make people take them seriously.
Continuing from the above, where did the myth that children are toxic come from?
- There's a theory that it had to do with transmittable diseases. Perhaps, in the early days, the monsters went the way of Native Americans and were quickly infected and killed in the hundreds by smallpox and the like. Maybe, once they started seeing humans (children) as toxic, they stopped getting so easily sick?
When Sulley scares a slumber party and fills up several canisters one after the other, each canister appears attached to the scream intake valve by magic as the last is removed.
- Mike is just that fast. Indeed, if you watch it frame-by-frame, he grabs new empties from behind where he is putting the full ones, from the camera's point of view.
Why do they need a silent countdown into the start of the scaring session, if they then start it with the blow of a horn?
- The whole scaring routine runs a lot like a showbusiness (rivalries between the scarers, the hero-worship they receive, the fact that their job is essentially to leave an impression on people who scare the pants off them just by being there) so the silent countdown seems adopted to add to the environment.
How did it take Mike and Sully so long to conclude kids laughing makes more power than screams? They used it to escape the antagonists.
- The whole movie takes place over the course of a few days, and much of the time is spent worrying that Boo might kill them, worrying that Boo might harmed, and dismantling an evil scheme. So it is really no surprise that they didn't put things together till the end of the movie.
Why are monsters banished to a mountain that's near a village of children's doors in walking distance?
- Keep in mind the village was a three-day hike away, through heavy snow and ice. Going out in a blizzard is very dangerous; Sulley and Mike were incredibly lucky not to get killed.
Then, you'd have to sneak past a bunch of humans that you believe are toxic - not just kids, but adults, and a whole village of them, instead of a family of 3 or 4.
Also, you've been exiled - presumably your property has been sold, you've shamed yourself and your family, nobody in their right minds would employ you, you'll probably be thrown straight back even if you can find a way.
Sushi resturant, when many of the monsters look like fish?
- There do exist predatory fish in Real Life. Humans are actually more closely related to certain types of fish (e.g. lungfish) than other fish are (e.g. sharks). Pixar's very next film validates that. Besides, technically sushi does not refer to the fish. It refers to the vinegared rice. Many sushi dishes don't even have fish (instead it's beef, cucumbers, eggs, that sort of thing).
- Even so, wouldn't eating something that looks remarkably similar to you be a bit disconcerting?
- Values Dissonance? They were chopped up into little pieces, so it helps the disassociation?
- Even so, wouldn't eating something that looks remarkably similar to you be a bit disconcerting?
There's a power crisis because are getting scared less easily, but shouldn't it be balanced out by increasing human population and thus, number of kids to scare?
- There's a limited number of "scarers", though. It does not matter if there's 50 or 100 kids who can be scared if you can only go through 25 doors a night.
- More kids to scare means more attention. Scarers are in a paradox: they need to get scares from children for power, but if they scare too many kids too many times humans will take attention and this could risk discovery of the monster world. From Mr. Waternoose's perspective, and in his mind he sees kids as batteries, he does not have to bother with all the difficulties of scaring in the outside world when he can just capture kids and extract screams from them.
So what keeps Randall from coming back? He was never officially banished. If Mike and Sully could find a closet in Nepal, it should not be too difficult for him to find one in what looked like the southern US.
- Nothing actually. Nothing keeps Randall from coming back. There are actually canonical comic sequels about Randall returning and trying to frame Sulley and Mike for various crimes.
- If  falls under the canon of the franchise, he did come back. It just took Vanitas rescuing him and rebuilding his door to accomplish it, since he "almost got turned into somebody's wallet." Evidently those hillbillies really must have done a number on him. Even though he did get back, they just beat him and sent him right back to where he came from (or so help him!)
- Assuming the comics and games aren't canon, I have a feeling the humans he ended up with ended up killing him with the shovel and sold his corpse so it could be turned into fine reptile leather.
How old is Boo? She has the drawing skills of a three-year-old, is potty trained, and looks and acts two, but she speaks like an eighteen-month-old?
- Word of God puts her at two. She is toilet-trained, which does not usually happen earlier than about three years old. It is possible she might also have a learning disability (maybe autism or Asperger's of some kind), since said skills are more developed than usual.
So what exactly DOES happen when Sulley opens the door and reunites with Boo?
- He opens the door and reunites with Boo. Presumably they remain friends. It is left to our imagination. If  falls under the canon of the franchise, Sulley and Mike stay after hours and have playdates with Boo (which evidently started not too long after her door got fixed).
Why destroy a door when it is deemed "dead?" Especially after the child fails to be scared of you just once? Why not put it on hold until a new family (and potentially a new child) moves into that house? Seems like a waste of a door. Where do new doors come from, for that matter?
- Possibly to keep down on storage. We see in the chase scene they have at least a thousand doors, and a dead door could be unusable for years on end. Monsters University shows that (at least some) new doors are created at Monsters University, tested, and then sent to Monsters, Inc. Presumably doors are also created and shipped at Fear Tech.
- Given the doors are painted/decorated to match, it's possible the doors are linked to the individual child and not the closet or room.
Regarding The Big Board...
- If all the other scarers have their surnames on The Big Board, why does Randall's slot say "Randall" rather than "Boggs"?
- Maybe that's the name he prefers to be known by?
- Some people are mononymous, they only go by one name.
- Doylist answer: error by the crew. Watsonian answer: Considering Randall's the second-best scarer for the company, maybe he, as a matter of hubris and Rule of Cool, decided to have his name rendered that way. Plus, maybe he was too embarrassed by his surname to have it used.
What's with the cone of shame? They're meant to stop dogs from scratching or biting a wound, so why would monsters need to wear one?
What happens if a kid switches rooms with an adult? People move houses and redecorate/change rooms all the time. Do the Monsters have a way to pick up on this, or something?
- It takes more than a day to switch to sleeping in another room. If the room is unusable it would be picked up on pretty quickly. The door would either be shredded or put into storage. Even if the swap wasn't noticed before a scarer went into the room, Monsters University establishes it as common for them to approach the child slowly, scouting out the room and considering the best approach for maximum scare power. As long as they don't rush into it, they'd have more than enough time for it to occur to them that, "Hey, there's no kid in here," and that they should bail on that attempt so as not to risk their exposure.
How many eyes does that purple monster have? When he walks out with Sulley and the other scarers, he has 3 or 4 eyes. However, when he is in his station, he has none and his helper dude PUTS IN a dozen or so eyes.
- They're actually two different monsters; just look at the score board carefully.
If a child's room has a sliding door for its closet, how would a hinged door portal work?
- One of the other closets throughout the house? They go through the coat closet, the towel closet, etc, then just use the bedroom door.
Why is there a door in the middle of the Himalayas?
- To banish people through, obviously.
Why are Randall and Waternoose so insistent to use Boo instead of some other kid? There's millions of other kids they can chose from and they would probably be better fitting. Boo may be scared of Randall, but she finds most of the other monsters "cute" or 'funny". In fact,
- Boo seems to be a recurring scare victim of Randall's. He may have chose her because she makes him feel 'superior" to Sulley. And given that the scream extractor was HIS invention, his motives might have been a pride thing to some extent.
When Boo laughed during the big escape scene, thousands upon thousands of doors activated for closets all over the world. Isn't that a security risk? Seems like there's good chance a human would have opened the door from the other side and either discovered the monster world or fallen to their death.
- Most of the doors in the door vault are stacked behind another door. Only a very small percentage of doors will be at the front of a stack or in transit, so if a child had opened their closest door, the chances were that all they would have seen was another closet door right in front of it. It was quite lucky for Sulley and Mike that every time they emerged from a door, it was always on the front of a stack or in transit.
Time in the monster world seems to go by in the same rate as the human one - at the beginning of the work day it's nighttime on the Eastern seaboard, and by the end it's nighttime in Nepal - nine hours' difference, matching a 9 to 5 workday which the clock shows the monsters also use. Shouldn't Boo's parents have noticed her missing?
- They probably did and panicked, but the story simply didn't touch on that.
What's with the odorant? For the most part monster society parallels human ones including hygiene such as when Sulley brushes his teeth.
- It probably helps with keeping their scary image - Sulley brushes his teeth to keep them shiny and not for the same dental hygiene reasons we have.
- A sequel comic made a joke about monsters smelling like flowers when they get sweaty. They just have different opinions on what smells good.
What's Randall's problem in the bathroom? He goes to the bathroom, and hears someone else is in there too, perhaps taking a dump. Does this really warrant busting open each stall?
- He didn't just talk about the incident. He mentioned he was involved in it, saying he was looking for Boo after she escaped, and mentioned a "machine". He would not want anyone to hear that.
Why was Randall "jobless"? We saw earlier that when a child was not frightened anymore, their door simply got destroyed and the monster would move on to other kids. So why did Sulley tell Randall he was jobless because Boo was not scared of him anymore?
- Sulley was being poetic, not stating Randall's literal job security.
How is Mike familiar with Greek Mythology? When coming up with ideas for how to get rid of Boo, he declares a giant wooden horse "too Greek". And if monsters are aware of mythology (presumably from participating in it), then should not the fact that they were able to interact with humans in the distant past without being poisoned tip them off that humans aren't toxic?
- Future Imperfect. A lot of monsters were slain by the heroes of Greek mythology, so that may have led to the belief that humans were deadly and that avoidance was necessary to ensure survival. As the years went by and monsters became more and more distant from humans, the exact means through which humans were seen as deadly were forgotten, so monsters just came to view them as being toxic to the touch.
When Mr. Waternoose claims Sulley will always be better than Randall, was he just being insulting, or is it supposed to be true? If it is the latter, why? The scare leaderboards show they're evenly matched.
- Mr. Waternoose knew the scream extractor was a gamble because it might not work. Top scarers like Sulley are still effective in scream collecting. It would be a double whammy for Mr. Waternoose to have to banish number one for discovering a scream collecting technique that might not even fly, so yes, he was being insulting, but mostly because he was annoyed he lost a valuable asset, coupled with Randall's arrogant attitude that was presumably fanning the flames.
How did every monster manage to transition to a comedian at the end? Surely not all monsters who worked as former scarers and assistants have the comical talent which is required?
- It is not hard to make a small child laugh. You don't need to be a comedian. You just need to eat a lot of beans or get hit in the junk (or anywhere). The later sequal Monsters at Work shows Mike gives the monsters coaching tips. Moreover, we're told that laughter is 10 times more powerful than the screams they were collecting before. So you would not need to be a master comedian in order to fill your quota for the day, just do something that'll get a giggle out of the kids, and you're good.
How was Boo able to climb up Randall's back without him noticing?
- Sneaking around and getting on peoples' backs without them noticing is kind of Boo's thing.
When Sulley and Mike get Boo to laugh in order to activate all the doors in the vault, we get a shot of a pretty sizable number of them. They all appear to be hanging from those hanger things, but there don't seem to be any tracks connecting the shelves where the doors are stored to the Scare Floors. How do they get them out of the vault?
- Presumably, they have a switching system similar to a railroad yard. Whenever they wanted to get a door out, they would just change tracks for the doors to ride on, except they would lift and shift the right tracks to get access to the right door. The guys in charge would also get the doors that were out in front first, scheduling it so each door behind it could be sorted out later.
How likely is it that all of the bedrooms Mike, Sulley, Randall, and Boo travel through during the chase through the door vault just happen to be vacant? How did no one see them?
- With Mike and Sulley not getting killed sledding down the Himalayas as well as finding doors that weren't blocked by a different door as mentioned in an above headscratcher, it seemed that luck was simply on their side that day.
- Maybe they did get seen, but people just dismissed it as something mundane. If you suddenly see a lizard, a green ball and a blue...whatever Sulley is zip past you, would you think that you just saw a bunch of monsters, or some guys in costumes or pajamas? Plus, Randall has his camouflaging powers.
Would not Randall have spotted the trio in the bathroom easily? I know he was not looking in their direction, but would he not have seen their faces in the bathroom mirror?
- Monsters University tells us that Randall has bad eyesight without his glasses, which he never wears, and he was also looking to the side when he knocked the stall open.
When Randall tries to intimidate Mike into telling him where Boo is, he brags that when he has finished revolutionizing the scaring industry, "even the great James P. Sullivan will be working for me!" Why? Would the scream extractor not result in mass unemployment for now-obsolete scarers, not people being forced to work for Randall? Randall himself later says that with the machine they don't need scarers so what's up with that statement?
- Just because they won't need scarers anymore doesn't mean they won't need operatives. Specifically, the scarers would be converted into child kidnappers and scream extractor operators, Sulley included.
Given that the plan seems to be illegal, Randall and Waternoose might still need traditional scarers to keep up a façade and avoid a CDA investigation.
If Mr. Waternoose and Sulley are all buddy-buddy with each other, why didn't he ask for his help with Randall's plan?
- He knows the type of guy Sulley is. Sulley is not the kind of person who's going to be okay with kidnapping anything to basically torture forever.
A kid claims there was a monster in the closet, parents would likely dismiss them as lying or wanting attention. But wouldn't a whole bunch saying the same thing be suspicious? That slumber party Sullivan scared seemed to be a big risk.
- A very real part of most slumber parties is all the attendants trying to make a monster appear or trying to re-enact some creepy urban legend. The parents would most likely know this and chalk it up to the shared hysteria a group of kids bring about in a group when they want to be scared.
And no matter what, jumping to the conclusion that monsters are using interdimensional portals to scare children is a reach for the parents. Maybe the parents would believe that they were just getting worked up over a giant stuffed animal, or something.
Why do Sulley and Mike go to such lengths to keep Boo a secret even early on? At that point neither of them were very attached to Boo.
- Sulley and Mike turning in the kid would be admitting that Sulley and Mike had the kid, which could be a complete career killer for the both of them, if not potentially going to prison for it. On top of that, Sulley, while not being as attached in the beginning, still did not wish Boo to be killed or something, of which he was under the impression the CDA was going to do?
How did Mike get back to the monster world from the Himalayas so fast?
- He may've just built another sled. Considering how much smaller he was, his would not have needed to have been as large as Sulley's, so he could've built one using the materials that were left over after Sulley left. He had enough time to make it back while Sulley made his way to the secret lab, saved Boo, and initiated the fight with Randall.
How would Randall and Mr. Waternoose have gotten away with their plot even if Sulley and Mike hadn't stopped them? They would have to explain where the sudden surplus of scream energy is coming from somehow.
- The commercial shown at the beginning mentions that the company was looking at alternative scare methods and scream technology - if their plan to extract the screams from Boo and other children were to go through, they could cover it up easily by claiming to have made a breakthrough with one of their other alternatives. (Which was probably the whole reason for the commercial.)
Why are even the monsters averse to Waternoose's kidnapping plan? It's only bad if you care about the kids.
- Even if they believe human children to be toxic, the monsters are aware that the kids have their own lives and families, The monsters are not... well, monsters. They fear children, but that does not mean they believe that children should be subject to horrific torture the same way humans look upon snakes or spiders - you might not care if they died, but you probably won't want to watch them suffering a cruel fate either.
What happens if a door is destroyed while it is open? Say, in the case of a door falling from a great height (like during the climax) and breaking apart.
- The connection is probably severed instantly.
Why did Randall reveal his evil plan to Mike and by proxy, Sulley? If he'd just kept his mouth shut the duo would still think Randall was just trying to cheat on the board and not have known about the scream extractor.
- The movie keeps a kid-friendly tone so one might not pick up, but Randall has it out for Mike and Sulley big time and tries to kill them multiple times - first by strangling Sulley, then trying to drop him in the warehouse. Plus, he's arrogant. He just wanted to gloat and them off his rivals.
Why is banishment a thing? It is a goal of monster society to keep their world's existence a secret from humans. So then, why do they deal with rogue monsters by throwing them out into the human world, where they could communicate with or be discovered by humans?
- The movies indicate the Loch Ness Monster, Bigfoot and the Abominable Snowman are all monsters that got banished, which seems a perfect demonstration that even if humans discover their existence it doesn't mean they will find out about the monster world as a whole.
- From what Mikey says, we can assume that those types of incidents are rare, but nobody ever forgets them. Think of it as the ultimate punishment only to be used when the Godzilla Threshold or Moral Event Horizon is broken. Besides, the banished monsters seem to do a pretty good job of hiding themselves anyway.
Why would Boo have flowers painted on the inside of her closet door, while the outside is blank?
- The design on the monster-side (inside of the closet, technically) is actually identical to the outside on the human side (this is most obvious when Sulley says goodbye to Boo before the door is shredded). The movie for some reason prefers to only show us the top half of the door, which is plain.
Why did Roz ignore Mike's request for the key to Boo's door? Even if she does not suspect Sulley and Mike of having the child with them, there's a picture of Boo in her file that could be matched easily to the one in the newspaper, and if Roz knew Randall had Boo's file the previous night, the conclusion to that is that he was the reason Boo got into the monster world. So why not take Mike into her office and interrogate him about what he knows or something?
- Roz didn't want to blow her cover, especially to someone with a big mouth like Mike who would have likely blown the whole operation and alerted the conspirators that the CDA was on to them. Besides, she had no way of knowing if HE was one of the conspirators (and given his lack of effort into filing his paperwork, she had reason to think he was blowing it off so he could partake in said conspiracy).
And considering Randall both has camouflage and is working with Mr. Waternoose, who owns the factory, it is doubtful he would need to go through Roz to get Boo's door key. That, and the key is found in his lab later in the movie when there's no reason for him to have checked it out a second time, so it is more likely that he swiped it to call Boo's door down the first time and then never returned it. Taken together, these mean that Roz would not have known what door Randall had been using or been able to tie it to the kid that got let in.
Do monsters think adults are toxic too? If not, then when do they think humans become not toxic?
- According to Monsters University, yes, they think all humans are toxic. It is just children are the only ones pursued since they are far easier to scare. Adults and teens won't scare easily.
How does the Abominable Snowman know about Bigfoot calling himself "King Itchy?" They live on opposite sides of the globe after being banished (the Himalayas in Central Asia vs. the Pacific Northwest in North America). Is there some way that they still keep in contact?
- Maybe Bigfoot and Snowman were banished to the same location originally, but then the authorities chose to relocate one of them because their combined presence in one area was attracting too much notice.
Previous headscratchers established parents won't believe childrens' words about a monster. But what about video evidence? Imagine: you're a child. You see a beast come to your room and scare you. You try to tell your parents, but they say it's just your imagination. Naturally, you'd want to prove your words. So next time you see the monster you grab your camera/phone and take a video. Now if there are multiple videos from different children, aren't the human authorities going to investigate these cases?
- No, they'd just write off the "monsters" as computer effects, or people in costumes, or puppetry; after all, there won't be supporting evidence (ie the closet door). Also established in previous headscratchers, even if the parents did believe them, it won't reveal/threaten the monster world as a whole because humans are still unable to travel to it.
- Except when the doors are in use, during scaring hours. If a parent was convinced that there was a real monster in their child's closet (and there undoubtedly would be some, in a world where flat-earthers exist) the obvious strategy is to camp in your kid's room at night with a shotgun at the ready. Hell, some parents do this already just to humor their children. One dead monster, or better yet, a live one, and their entire world is blown wide open.
- Luckily for the monsters, they clearly have ways of keeping tabs on the human world, in order to build new doors and know about children's fears and such. They would know in advance not to try scaring any child whose parent was expecting them to show up.
When Mike makes up the Bring Your Obscure Child To Work Day, Mr. Waternoose replies "Must've missed a memo." What kind of CEO would miss a memo, or even allow a memo about a special day be made without his permission?
- He's probably not fully he convinced he missed a memo; he's just willing to go with it because he has more pressing issues to attend to and is on good enough terms with Sully to allow it.
- He is the boss of a major energy corporation; he presumably deals with lots of memos and important corporate business on a daily basis (and has his secret child-abduction scheme running on top), so it's not entirely unlikely that a memo about something relatively trivial like a family visit day might slip his memory. He probably just assumes it's one of the less important things that, assuming it was even considered important enough to cross his desk to begin with, he just scanned and approved without really thinking about it too much.
How did Mike get all of the CDA agents to quietly watch the footage of Waternoose revealing his evil plans?
- I mean, earlier they were chasing him because they thought he had Boo, so surely they wouldn't have just stopped because he simply told them to.
- It's possible he had enough of a head-start to lead them back around to the training simulator after Sully and Waternoose were inside, with time to activate the camera feed and then hide himself so that the CDA agents would notice what was going on inside the room before zeroing in on him. Once they were clued into the fact that Waternoose was in on the whole thing, Mike would've had a chance to fill in the the details for them while the rest of Sully's side of things was being recorded. Hence why he plays back over the critical parts of the scene afterward.