Every year since she'd first been trusted to slather fabric glue all over a ratty old shirt and stick brightly-colored craft store feathers on top of it on her own Boo had made her own Halloween costumes. From those humble beginnings her talent at it had only grown, as over the years she'd taught herself how to sew a straight seam, how to properly fit her creations to her body, how to work with materials that needed more care than whatever junk was lying around in the arts and crafts bin her mom had prepared for her while she was little. If someone had given her a length of fabric and told her to make a normal shirt or dress or something of the sort out of it she wouldn't have known where to begin, but if they'd asked her to shape it into a mask so inhuman that they would have needed to look closely to make out the girl peering through it then she didn't know a single person who could match her talent.
And they'd tried. Every year the Middle and High School in her district had a costume contest on Halloween that any student could enter, and for six years running she'd been the winner of the prizes both for her own grade and for the best costume overall. It was the only time of year that she became something a little like popular, instead of just being that odd girl who told everyone to call her 'Boo' and had a tendency to zone out and stare at closet doors without warning. People always gibbered at her about how awesome the things she made were, and how cool it was that she'd invented them all herself instead of just putting her own twist on the same old witches and vampires.
Of course, the change in attitudes was usually just because they were working up to asking her if she'd make costumes for them too, but she didn't really mind. Sometimes she even agreed to help out—as long as they didn't mind her just giving them advice and not building their costumes from scratch—if it was someone she actually counted as a friend during the rest of the year or who never really bothered her even if they weren't close. But she never told any of them where her ideas came from; everyone else always forgot about their monsters once they got too old for their laughter to work and were left alone at night, so there was no way that they'd understand if she told them that she based the creatures she made on the photos Sulley brought to show her his world and on the hazy half-recollections she had of her one visit there.
Her parents had thought her hobby was weird at first, especially as they became complex enough that she needed to start them earlier and earlier in the year and when she got a part-time job as soon as she was old enough primarily to buy more expensive construction materials, but over time they got used to it. In fact, they became proud of it; more than once she'd overheard them bragging about the incredible future she had waiting for her as a costume designer in Hollywood. It wasn't something she'd ever really had in mind for herself—she'd always kind of hoped that maybe, just maybe, by the time she was old enough to move out and start living her own life the people in the monster world might have gotten comfortable enough with humans that she could try finding a life over there—but when she stopped to think about it making her own monsters for a living wouldn't be so bad.
As long as they didn't try making her work on horror movies. Her monsters were made to be interesting, or to be funny, or to make you want to look closer to find all the strange details that set them apart from humanity. Some of them might frighten some people, but they were never intentionally scary.
She'd just finished her latest costume, only two days shy of that year's Halloween, and she didn't think that it was being too proud to say that it blew all her past work out of the water. She'd been working on it all year long, ever since she'd first gotten the idea and realized just how much time it would take to fully realize it.
It was a reptilian monster, each and every little scale painstakingly cut out of thin faux-leather and sewn into place with one or two tiny stitches. She'd poured over pictures of snakes and lizards as she worked, examining the patterns on their scales and the way they fit together, and she'd made her own patterns by painting each scale with iridescent nail polishes, dark blue or clear or pearly white, that left it shimmering like an oil slick when light moved across it. The end result all flowed together like a real skin, not a seam to be seen unless you looked very closely to find the line of hooks that held it closed.
The legs were longer than hers, designed to hide a set of drywall stilts that she'd been practicing walking around in for weeks so there was no chance that she'd fall over flat on her face in front of the entire school, and ended in long-toed feet with curved metal claws. The gloves were too long as well, an extra joint made out of wood hidden at the end of each that would attach to her real fingers with tendons made of rubber bands to allow them to bend, and her ring and pinkie fingers would be bound together to make her four-fingered like a cartoon character. The body itself underneath all the scales didn't have much to hide its humanity, but it was those details, and the way they'd make her move in a way that wasn't quite right, that would end up latching onto people's minds.
Boo had spent a lot of time learning about the uncanny valley.
But it was the mask that was the gem of the costume. For the first time ever she'd gotten to play with latex, and to make a cast of her face so it would fit just right. With that she wiped her humanity right away as much as she was able. Her nose flowed into her cheekbones flowed into the frill of black 'skin' she'd created to mimic her own hair. Her brows turned into delicately curved horns that curled back over the ridged holes that served as ears. The lashless eyes were built around the black lenses she'd popped out of a pair of sunglasses, serving the lizard illusion while letting her see perfectly well (if dimly) from behind them. The only thing she'd left unchanged was her mouth, which would be left uncovered by anything other than makeup that she'd found to match the color of her scales with the edges of the mask glued carefully down around it. It would break the realism a little if anyone looked closely enough to find the line where mask met flesh, but not as badly as it would if her mouth couldn't move when she talked.
She was just fiddling around with a few more finishing touches--buffing up her claws, twining a ribbon through 'piercings' in her frill--when she suddenly heard voices coming from her closet. She whipped her head around, beaming joyfully, but nothing ended up happening except for a familiar and much-loved voice shouting indistinctly in reply to some other voice in the distance. This happened from time to time, somebody would catch sight of him when he was about to come for a visit and he'd have to quickly distract them from wondering about why he had a door hooked up in a place that, from what he'd told her, no door should have been.
He'd always told her, very seriously, that when that happened she mustn't go through herself looking for him even if he left the portal between their worlds open. That she just had to wait, and he'd get back to her as soon as he could. That they were very lucky that he was able to visit her at all, and if anyone caught her wandering around in the monster world again they make sure to separate them for good. That humans still weren't allowed to cross over, even though nobody really still thought that they were harmful.
Humans weren't allowed, but...
It really was her most realistic costume ever.
Stepping through the closet door was the most thrilling thing she could remember having done in her life. Even though she was sure that her costume was perfect a paranoid side of her couldn't help suspecting that every person that went by was about to yell 'Human!' when they saw her.
But they didn't. A few people looked at her, but then they just glanced past, or flashed her a smile (or, in a few cases, what she assumed must be smiles though they came from mouths too fangy or lipless for her to be absolutely sure), or said hello. She couldn't help but start to strut her stuff a little as she went on, as much as she could on stilts at least. She wasn't weird little Mary anymore, she was Boo, monster among monsters.
She even worked up enough confidence to speak after awhile, when she realized that if she didn't find Sulley soon she might miss him on his way back to her door. She decided on a girl who looked like the result of a flamingo somehow mating with a dog, her head having both a long hooked beak and fluffy ears like a poodle. "Excuse me, have you seen Sulley around?" When the question just got her a surprised look she hesitantly went on, "Um, sorry... I mean James Sullivan?" She had to drag the name up from the depths of her memory; just calling him 'Sulley' instead of 'Kitty' was weird enough, and most of the time she practically forgot that he had a full name besides that.
Finally the girl snapped out of whatever place she'd zoned out to. "Of course, Mr. Sullivan! He passed by not five minutes ago, taking some paperwork to his office I think. Just turn right at the end of the hall then keep an eye on the nameplates to your left." Boo thanked her and went on her way, and practically the moment her back was turned she heard the girl rush across the hall to another monster and start hissing, "Did you hear that? She called Mr. Sullivan Sulley. Have you heard anything about--"
Whatever she may or may not have heard about was cut off when they vanished into a room and clicked the door shut behind them. But that didn't matter any to Boo, she was there to see Sulley not to eavesdrop! Now that she knew where he was she practically skipped her way in the direction the girl had indicated, except that skipping was way beyond her current stilt-walking skills.
It didn't take her long to find the right office. She didn't even need to check the nameplate; the door was wide open so she could see him inside. He was standing over his desk shuffling through some papers with a look on his face that made it obvious that he just wanted to get out of there. It made her happy to think that she was probably to reason for that look, that he was trying to get to her door as soon as he could and wasn't happy that someone had reminded him of work that he needed to get done before he could.
It didn't look like he was going to notice her on his own, so she knocked on the frame of his door. "Hello!"
He only glanced away from his papers to look at her for a split second before he started to say, "I'm sorry, Miss, but we're closed for the..." He trailed off and looked up at her again, his gaze moving lingeringly up her body, then cleared his throat and went on, "But, uh, if you need help with something I'm sure I could find a minute or two."
"I knew you could!" she said, grinning at him. She closed the door behind her as she entered the office and walked slowly over to him, more careful than ever not to lose her balance; falling on her face in front of her school might be bad, but falling over like an idiot in front of him would be mortifying.
He didn't say another word, just gulped once as she got closer. The only sound was her scales shifting against each other with a noise like rustling leaves and the occasional muffled voices of people passing by outside. He kept his eyes fixed on her and she looked back until she was standing right in front of him, then she suddenly laughed brightly and said, "Oh my God, I'm almost as tall as you!" and flung her arms around his neck.
He held himself stiffly, gingerly raising one hand to rest it against the small of her back, and said, "I'm... really sorry I need to ask this, Miss, but do I know you?"
She laughed again, nuzzling her face against the fur of his shoulder which was just as soft and warm as it had always been. "Wow, is my costume really so good that even you can't recognize me, Kitty?"
He answered with a choked noise, then exclaimed, "Boo?!"
Sulley couldn't stop staring as he walked through the halls of the company with Boo at his side. Luckily she didn't seem to notice that anything was out of the ordinary, she just went on chattering happily about what had been happening in her life lately.
He'd made a token attempt at convincing her to turn right around and go back to her world that she'd laughed right off with an insistence that if even he hadn't recognized that she wasn't a monster, who else would? He couldn't deny that she was right, and he also couldn't deny her when he knew just how badly she'd wanted to see the monster world again now that she was old enough to hold onto the memories.
But the problem wasn't that someone might recognize her as a human. The problem was that she'd done so well at making herself look like a monster. She'd told him about the costumes she made once or twice before but he'd never had a chance to see one, the Halloween season always being busier than usual so he couldn't find nearly as many opportunities to sneak away to the human world. He'd never known how well she could disguise herself, or maybe he'd have been able to brace himself for it.
Then again, maybe not. It's not like he'd have been expecting her to suddenly show up in his office, no matter what the circumstances. Maybe she had expected him to recognize her, but from his point of view he'd just been through the not-exactly-unpleasant experience of having a lovely young woman enter his office, slink up to him, and wrap her arms around him.
And then that lovely young woman had turned out to be Boo. And he half-felt like he should run his genitals through a meat-grinder for daring to have less-than-pure thoughts about her.
But even now, knowing who she was, he couldn't shake those thoughts. The only thing that he could recognize as being Boo on her now that he looked closely was her mouth, and even that he realized, for the first time, looked like it would be wonderful to kiss. And maybe, maybe, if it had just been the features of her costume that he was attracted to--the sheen of her scales, her wide dark eyes--he could have shrugged it off. Sure, he'd feel embarrassed about having a costume catch his eye, but at least it would have nothing to do with the person inside the costume.
Unfortunately, it was just as much the body within the costume that had caught his eye, the curve of her hips, the strong-looking thighs, the things that were completely her. And now that he'd seen it he couldn't stop seeing it, and that was just wrong on every level.
Just as wrong was that he could see other people who worked in the company watching them as they left the building, Boo clinging to his hand and pulling him towards the first thing that caught her eye. Watching, and judging and... approving, judging by the smiles and nods he got from them. Nobody in the world, or at least the small part of it they were passing by, seemed to see anything wrong with her staying plastered to his side, and that made something in him feel like maybe, just maybe, they were right.
And that was just as wrong as anything else.
He took her walking through a sculpture garden, letting her loop her arm through his and lean against his side so she was a little more steady on her feet, and she thought that he was just taking a chance to teach her about the history of his world that she wouldn't have been interested in hearing the first time she was there as they walked by statues of famous leaders and heroes. Which he did.
He took her to dinner, and she thought, well, of course he would. It was time to eat after all. And it might have been a very nice restaurant, but it was also a very special occasion, her first time back in the monster world since she was two, so that was completely acceptable.
Then he took her dancing, and she realized that they were on a date, even if she didn't know if he thought of it that way himself.
The realization was strange, but not unpleasant. If she was going to suddenly realize that she was on a date with somebody, who better than the man she adored most in the entire world outside of her family? She certainly wouldn't want it to be one of the few men she adored more who were in her family, because ew. And maybe it should bother her that he was huge, and furry, and had horns and claws, but how could it? He was Sulley. Her Kitty. He was more of a person to her than most of the humans she saw at her school or in her neighborhood on a daily basis, who passed by without making any sort of impression on her life.
And, okay, she knew just enough about psychology to realize that the fact that she loved him so much could be an issue all on its own. That there were all kinds of muddy consent issues when it came to someone you'd known and looked up to all your life, but... pah. If it actually looked like he was consciously trying to seduce her she might force him to keep his distance, though it would break her heart to need to do so, but it didn't. He'd been nothing but a perfect gentleman, not even touching her except when she made contact, it was just that he was a perfect gentleman who was taking her on date-like activities.
Which was why she didn't doubt her choice to grab his hand at the end of the evening, before he had a chance to turn back toward his company and the doorway home within it, and said, "I want to see your home again, Kitty. So I'll remember it this time."
He hesitated, but eventually told her, "I can show you if you want, but it isn't the same apartment, Boo. I found a one-bedroom place years ago, after Mike married Celia and moved out."
"I remember so little that you could have lied and I never would have known it was a different place, you know," she told him, and shrugged. "I still want to see."
"Okay then. Next stop, home."
It seemed like there should be something special about monster apartments, something that would make it obvious just from looking around that it wasn't a human who lived there, but there wasn't really. The furniture was bigger than normal, the pictures she could see held people who came in every color of the rainbow and had fur, or fangs, or horns, or all of them at once, but it could just as easily been the home of some eccentric B-movie fan.
It could have belonged to a human, but it definitely belonged to him. She could see his favorite colors, books on his interests, dozens of little things that made her think of him. Even though she'd never been there before she immediately felt comfortable.
As soon as the door shut behind them and there was no longer any chance that another might spot them she reached up to pull off her mask, wincing a little as the glued down spots tugged at the nearly invisibly fine hairs on her face.
"Boo!" Sulley yelped. "Don't forget that we still need to get you home." But even though he was concerned he couldn't hide the way his face softened when her real face was revealed, and after a moment he stopped even bothering to try, reaching out to gently touch her cheek with one claw and say, "There you are."
"Here I am," she agreed, smiling warmly up at him. "But do I really need to go? As long as you don't try to make me sleep on newspaper on the floor again I'd be glad to stay." She reached up to twine her fingers through the soft fur covering his cheeks, very aware of the way his eyes widened enough that they almost seemed to bulge out of his face and how he gasped through his nose in a sharp hiss. "Why don't I stay?"
What better way to end a date and start the rest of an evening, however it might go, than with a good-night kiss?
He didn't know what was happening. He didn't know how his day could have veered so drastically away from what he'd had planned, how instead of sneaking off to Boo's room to play with her the way he always had before he could have wound up stumbling into his room with her practically attached to him by the mouth.
He had to hold her so gently, her human body more delicate than any monster's, but instead of feeling like an irritating hassle it only seemed right. He cared for her more than any other girl--no, woman, in a situation like this he had to think of her as a woman--he'd known, so why wouldn't he treat her with more care as well?
It might have been the costume that first made him feel attraction to her, but when she slowly pulled it off, shimmering scales giving away to smooth pale skin, he guiltily realized this was much better. The willowy reptile girl might have been beautiful, but she was a beautiful stranger; he didn't know her for the attraction to be anything more than physical. But the body hidden inside of her was dearly loved, even if he'd never ever thought of it was something to be turned out by before.
When he'd lead her into his room he wasn't even sure what they might be able to do with each other, though he was sure that they'd be able to work something out. What humans looked like underneath their clothes wasn't exactly a well-studied subject for monster-kind. But he relieved—relieved but on some level a little sad that he had no easy excuse to let her down gently and send her back home if he suddenly came to his senses—that the way she was put together was just about the same as what he'd expect from a female monster, just on a smaller scale. There was even a patch of fur between her legs, tight coarse curls.
"Boo..." he managed to keep his head enough to say, "Boo, are you sure you want to do this? I'm pretty sure no human and monster have ever tried anything like... this before." It didn't matter that she was the one pushing him to the bed and taking him in her hand, he had to hear her say it. He had to be sure.
"I am," she said, and she certainly did sound confident. "I do. I never thought of it before, but if I have a choice between this and just going home and one day finding a normal human boy to date it's no contest." She laughed and fell forward on top of him, burying her face in his cheek, and happily confessed, "I have almost no clue what I'm doing but I don't feel nervous at all, because I couldn't ever feel nervous with you. That seems like a pretty good sign, right?"
It was good enough for him.