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A Fiend in Feline Shape

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It’s not that Derek doesn’t like cats, exactly - he’s pretty neutral about them, doesn’t really feel strongly one way or another. Kittens are pretty cute as far as cute things go, and he has rescued two cats total from perilous situations in his lifetime (one at the very top of a tree while its elderly owner went inside to call the police, and another that got dumped out in the Preserve with no claws that he took to Scott to take to… wherever random stray cats go). 

He’s not the type to say he thinks all cats are assholes, because he understands their body language. He doesn’t mind the feral colony that lives in the Preserve either, especially once they all get trapped, fixed, and set loose again. Derek’s got nothing against cats.

Cats, however, really hate Derek.

The one in the tree had given him some wicked marks through his shirt that had healed before he was even on the ground with it, and the one he’d given to Scott had been spitting mad and wrapped in a towel when he handed it over. It hadn’t calmed down until Scott had dropped it into a cat carrier, where it essentially hunkered down and hissed at them from behind the plastic.

“Huh,” Scott had said, with a grin. “I usually don’t have this problem. Every other cat I know finds me pretty calming.”

Derek, when he bothers to think about it, chalks it up to being a born werewolf and an Alpha, and goes on his merry way.


The thing with Stiles starts as kind of an accident between one research night and the next. By which Derek means all of that weird, cut-it-with-a-knife tension that’s been plaguing them for years comes to a head late one research night, they get absolutely no research done, and have to try again the next night.

Honestly, thank whatever gods are out there for Lydia, because that was a vicious cycle that lasted for at least three very naked days.

Now Derek actually occasionally uses the front door at the Stilinski house and comes to Stilinski family dinner on Sunday nights when the town’s not busy trying to kill them. It’s through these relatively domestic dating adventures that Derek learns a lot of strange facts about Stiles, as well as a few not-so-strange facts. Considering Derek can admit in the privacy of his own mind that he’s pretty well head over heels for Stiles, he soaks all of this information up like a “grumpy lovestruck sponge” - or, at least, that’s what Cora calls him.

For example, Stiles can cook. Derek knew this in an objective way before they fell into bed and didn’t come out again for three days, but it’s only after attending Stilinski family Sunday dinner that Derek realizes just how handy Stiles is in the kitchen. After a month of Sunday dinners, Derek starts to see a pattern - it’s always fish. Different meal every week, but it’s always fish. 

“Apparently, it’s good for me,” the sheriff says by way of explanation when Derek finally asks if it’s a tradition or something. 

“Eating at least one serving of fish a week has been linked in studies to reduce the risk of heart attack or stroke!” Stiles hollers from where he’s pulling the tilapia out of the oven in the kitchen. 

“Considering we have it two or three times a week, I should be well-protected,” the sheriff says, shaking his head a little with a smile. “It’s one of his favorites, he just doesn’t like to admit it, so he uses me as an excuse.”

Derek files that information away under date ideas, and makes a mental note to look into nice seafood restaurants for special occasions. 


That’s just the first of the weird things Derek starts to notice about Stiles. As time goes on, Derek picks some other things up too.

Like Stiles has this uncanny ability to squeeze into spaces that he really should not be able to as an athletic nineteen-year-old boy. Derek has witnessed him shimmying through barely-open windows after he got locked out, has watched him somehow squeeze through just-big-enough bars in a hunter’s cage to retrieve the keys to get everyone else out, has found him somehow asleep underneath his own bed, and has watched with a mild sense of horror as Stiles once folded himself into a suitcase in the name of scaring the hell out of Scott. 

“If he fits, he sits,” Scott says one day when they find Stiles napping happily wedged between the couch and the wall. Scott’s got that look on his face like there’s some inside joke there that Derek doesn’t get.


Derek is already familiar with Stiles’ oral fixation, as it was first the bane of his entire existence right up until it very much wasn’t , and now it’s distracting in a completely different way. He just was not previously aware that it extends beyond things like straws and pens and hoodie strings, straight into things that should probably not be chewed on. 

“Dude,” Scott says for the third time at movie night. “ Stop chewing on my blanket! It is hand-crocheted, my grandmother sent it to me!” 

“Sorry!” Stiles apologizes for the third time at movie night. “I can’t help it, Blair Witch makes me anxious and it’s… you know… yarn.”

“I know it’s yarn, you’re gonna give yourself, like, an intestinal blockage or something, and I deal with enough of that with cats at the clinic. Stop chewing on it.” Scott gives the blanket a tug so that it’s fully out of Stiles’ hand.

“If I didn’t get an intestinal blockage from that time I chewed up all that Christmas ribbon, I’m not gonna get one from chewing on your blanket.”

Lydia blows out an annoyed sigh from across the room. “Can we all just agree that this is a really weird exchange and shut up so we can watch the movie?”

Scott and Stiles go quiet, Stiles glaring at Scott for a second before they both turn back to the movie. About ten minutes later, Scott reaches over without looking and yanks the blanket out of Stiles’ mouth, balls it up, and tosses it aside to Stiles’ indignant cry. Finally, Stiles grumbles, shifts so he’s turned more towards Derek, nestling into where he’s leaning against Derek’s arm, rubs his cheek against it in that way he does. 

And immediately begins chewing on Derek’s sleeve.


It’s just a collection of what Derek starts to call endearing parts of Stiles’ personality. He’s got a strange fascination with houseplants but none of his own, and seems to actively detest lilies. When Derek and Stiles go over to help Scott with… honestly, Derek doesn’t remember exactly why they’re there, because he was pretty distracted when Scott was talking about it on the phone. Stiles had been making his case for Derek to just hang up at the time, and it had been pretty convincing.

Scott doesn’t let them in right away though. Instead, he stops Stiles with a finger pointed at Stiles’ chest before they walk into his apartment. 

“What,” Stiles groans, dropping his head back like he has never been so inconvenienced in his life.

“Mom bought me a bunch of plants as housewarming gifts,” Scott says.

Strangely, that makes Stiles perk up.

“You can’t eat any of them,” Scott goes on. 

“Eat them?” Derek mutters in confusion. 

They ignore him. “What kind?” Stiles asks. “I’m not gonna eat any! I’m just curious.”

Scott narrows his eyes at Stiles for half a second before stepping aside to let them in. The plants are on the kitchen table, and there are boxes all over the floor. They’re all in various states of unpacked, and Derek is momentarily distracted as he very suddenly remembers what he agreed to do today without paying attention before hanging up on Scott.

“Oo, spider plant,” Stiles says, fingering the leaves. “Money tree, nice succulents, Scotty, those are pretty. African violets aren’t too hard to take care of - oh, Scott, really ?” He shoves pots out of the way and pulls another one forward to the edge of the table with a disgruntled look on his face.

“You definitely can’t eat that one,” Scott points out.

Stiles rolls his eyes at the plant, which is, Derek thinks, a peace lily. “What do you have against the plant?” Derek asks. “Also, why is eating any of these on the table?”

“That’s the point, eating them is not on the table,” Scott says, and turns his attention to Derek. “Stiles doesn’t like plants that are poisonous to cats, so I’ll be surprised if-”

There’s a crash, suddenly, like the sound of a ceramic pot hitting a hardwood floor. 

“ survives the day,” Scott finishes with a sigh.

Sure enough, when Derek and Scott look over, the peace lily is lying in a sad mess of potting soil and ceramic shards at Stiles’ feet. Stiles, for his part, looks as innocent as one can possibly look when they’ve very obviously committed a crime.

Which is to say, Stiles looks so guilty there might as well be a wanted poster. “Oops,” he says, not at all convincingly. “Well, now eating it is literally off the table. My bad. I’ll buy you a better plant to make up for it.”

Later on, after Scott has made Stiles clean up the mess, Derek comes in just in time to see Stiles pluck the tip off of the spider plant leaf and stick it in his mouth. 

The mystery deepens.


That seems to be it for the oddities that make up Stiles’ personality. It’s not like they happen often - Stiles doesn’t take leaves off every tree as a snack or anything, eats more curly fries and pizza than fish any day of the week, and only chews on random things when he’s incredibly nervous, like during a horror movie or when they’re hiding behind a giant rock in an effort to avoid the notice of a forest troll. He may have a habit of knocking things over pretty frequently, but that’s honestly more due to his natural clumsiness and not out of any malicious intent. In addition, his weird ability to basically become a liquid comes in handy when he needs to hide in a small space to wait for rescue.

So when Derek shows up for Sunday dinner about six months into dating Stiles and the first thing that greets him on the porch is a very prim and proper looking orange tabby sitting next to the door, Derek is confused to say the least. The cat doesn’t hiss, doesn’t look in any way perturbed by Derek’s presence - in fact, it barely looks at him once before it looks away again, and lifts a paw to scratch at the front door.

Derek slowly reaches out to knock, but he doesn’t look away from the cat until the door opens to reveal Stiles. Then, the orange tabby slips inside, winds through Stiles’ legs, and disappears into the house.

“Did you get a cat?” Derek asks, stepping inside and letting Stiles wrap him up in a hug. He gets a little distracted from his own question when Stiles kisses him.

“Wait, what?” Stiles pulls back from the kiss, suddenly confused. “No? I’ve always had Railway Cat, have for, like, eight years now. I have White Cat too, she’s around somewhere. You didn’t know I had cats?” He’s got a concerned look on his face. “Is your nose broken?”

Derek shrugs awkwardly. “I’ve never seen them before,” he says. “And there are… a lot of stray cats out there, you just kind of filter the smell out or you’re just… constantly smelling housecat.”

“Huh.” Stiles is giving him a weird look. “So you’ve… never smelled cat on me? Never noticed any fur? Nothing strange at all?”

For a moment, Derek pauses, convinced he’s somehow offended Stiles. “No,” he finally admits.

At that moment, a very fluffy white cat appears at the foot of the stairs, meowing in an insistent manner. Derek can only assume that this is the aforementioned White Cat. 

“Oh,” Stiles says after White Cat apparently says her piece and starts heading up the stairs. “Well, uh. I guess we’ve… talked it over and they’ve recently decided you’re not going to eat them after all. Welcome to the family, I guess. Hey, Dad!” Stiles calls. “Derek didn’t know we had cats!”

That seems to be the end of it, right up until White Cat makes herself at home on Derek’s lap halfway through dinner. She settles down and immediately starts purring like a motor boat, like Derek is in no way a threat. She doesn’t even go for his fish, instead seeming perfectly content to be a fluffy loaf on his legs.

“Oh,” the sheriff says, like this is somehow a revelation.

Stiles rolls his eyes. “Victoria, you know better. You can push her off, babe.”

The thought only sits with Derek for a second before he’s shaking his head and going back to eating. “I don’t mind,” he says, and if anything, White Cat purrs even louder.

The sheriff - and really, it’s been six months, Derek should probably call the man John, but old habits die hard - is smiling like he’s just won some kind of prize, completely out of proportion for the simple joy of a cat purring on Derek’s lap for the first time in Derek’s life. “Are you a cat person, son?”

“Uh,” Derek replies eloquently. “I like them fine, cats just hate me. This is the first time one’s ever seemed to even tolerate me - usually they’re hissing at me by now.”

“I assure you, Derek.” Is there some kind of twinkle in the sheriff - in John’s eye? “I guarantee you that there is a very special cat out there who doesn’t just tolerate you, he loves you.”

Stiles chokes on his rice pilaf, splutters and coughs, but waves Derek’s hand off when he reaches to pat his back. “Dad!” Stiles says hoarsely. “Come on.”

“Uh,” is what Derek manages, because this is probably the strangest Sunday dinner so far. “I think my apartment needs a deposit for a pet? So I probably won’t go… to get one.”

“That’s probably for the best, some cats can get very jealous.”

“Dad,” Stiles says in that warning tone, like his dad is about to reveal some life-changing secret.

“And you should know, you don’t choose the cat.”

“Dad .”

John will not be deterred, however. “Cats choose you. They latch on, worm their way into your life, and it’s really hard to let them go.”

“Okay!” Stiles says in a very definitive manner, as John finally acquiesces and goes quiet with a smile. “That’s enough about Dad’s weird cat advice, can we please move on?”

There’s a brief moment of silence, broken only by White Cat’s purring. “I have a question,” Derek says. “It’s about cats. Sorry.”

“You’re allowed to talk about cats.” Stiles points to his dad. “ You are not.”

“Yeah, yeah.” John stands, heads into the kitchen to clean his plate and probably sneak an Oreo from the pack both Stiles and Derek are pretending they don’t know about hiding in a cake pan on top of the fridge.

“Is Railway Cat named Skimbleshanks?” Derek asks. His plate is clean, and he puts down his fork to very, very tentatively brush a hand over White Cat’s back. “You called White Cat ‘Victoria.’”

Stiles’s expression shifts from an annoyed one aimed at his dad to a suddenly pleased one, cheeks pinking. “Yeah, you’ve seen Cats?”

“I saw an off-off- off -Broadway production.” Laura had taken him. It was, he remembered, the first thing in months that had made him smile. “I watched the DVD we had every day for a week after. Munkustrap was my favorite.”

Oh, now Stiles is wearing one of Derek’s favorite expressions - that soft one, where he’s smiling in that way that makes Derek want to wrap him up in a comforter and keep him safe from all of the bad things that exist in the world. “It was my mom’s favorite. We watched it… a lot after she got sick. Munkustrap was my favorite, too.”

White Cat jumps down from Derek’s lap suddenly, only to jump up on Stiles’ a moment later. 

Stiles looks down at her, scratches gently at her chin. “What, you think just because he lets you sit on his lap at the dinner table that I’m gonna let you get away with it?” She purrs, and Derek watches with a warm feeling in his chest as Stiles very clearly lets her get away with it. 


The cat that appears on Derek’s pillow a week later is a lean gray tabby tomcat with little white socked feet. Derek is a little alarmed that he slept through the cat both getting into the apartment and climbing onto Derek’s bed to sleep beside him, but there seems to be no murderous intent in the way that the cat is fast asleep, stretched out on its back with its tummy exposed and its legs curled in. The thought of a cat snoring has never crossed his mind, but there’s a tiny little rough sound that is definitely happening on every quick little inhale, and Derek can’t help the way that he is completely and utterly charmed. 

Now that he’s familiar with White Cat and Railway Cat, he can say with some certainty that this strange gray cat smells an awful lot like the two of them, and an awful lot like the Stilinski house. It has to be that Stiles got another cat or something, or maybe even dropped this one off, because this cat smells almost exactly like him, had to have been in the Jeep or his bedroom, if not literally on top of him.

The cat jolts awake at the sound of Derek’s ringtone, orange eyes snapping open and ears perking at the sound. Derek grabs the phone and rolls onto his back, rubbing at his eyes as he answers. To his surprise, the cat clambers up onto his chest and purrs, curls up like it’s going to go back to sleep.

“Derek, are you there?”

Belatedly, Derek realizes that he’d never actually said anything after accepting the call. “What, Scott? It’s…” He doesn’t actually know what time it is, didn’t bother checking, but there’s not a lot of sun coming through the curtains yet, so he finishes with, “early.”

“Have you seen Stiles? Is he with you?” Scott’s worried, but not quite frantic.

Derek carefully pushes the cat off his chest, rolls out of bed to grab his jeans off the floor. “No. Why? What happened?”

“I just woke up to a voicemail of him telling me that someone was following him, but that he was going to try to make it to your apartment. Cut off halfway through.” 

The panic had been steadily rising as Scott had been talking, but Derek tamps it down as he strides into his living room, goes to his window. “His Jeep’s not in the lot,” he says. “I’ll get my keys and meet you…”

Derek trails off as he notices that the window isn’t open. The door is locked, too, deadbolt thrown. In fact, as Derek walks through the apartment backwards, there isn’t a single entry point, absolutely no way for the cat to have gotten in. 

He gets back to the living room and looks around. There, on his coffee table, is the spare key that he had taped to the bottom of the welcome mat so that Stiles would stop picking the lock to get in when he forgot his copy of the apartment key. 

“Derek?” Scott asks, impatient.

He hears a meow, and the gray tabby jumps up onto the table to sit next to the spare key, long tail slowly swishing back and forth and eyes blinking slowly at Derek. 

“Derek, is that a cat ?” Scott sounds exhausted, but relieved. “Actually, let me be more specific. Is it a gray cat? Little white feet? Looks a little smug about how cute he is?” 

Suddenly, every little weird thing that Derek’s observed about Stiles makes sense. Of course Derek wouldn’t wake up in the middle of the night if Stiles came in - Stiles is supposed to be there, no matter what form he’s in. It’s not even the first time that he’s gone to sleep only to wake up with Stiles draped on top of him, because Stiles isn’t a threat. 

“Do you want to figure out where the Jeep is?” Derek reaches out and drags his hand down Stiles’ furry back, from between his ears and all the way up his tail. Stiles arches, purring happily, orange eyes closing. Then, Stiles slips out from underneath his hand and jumps down, silently pads back into Derek’s bedroom. “You’ll also want to see if you can find his clothes, his wallet’s probably still in his jeans.”

When he hangs up with Scott and heads back into his bedroom, he finds Stiles sitting on his bed in a pair of Derek’s sweats and one of Derek’s t-shirts. He’s got the neck of it in his mouth between his teeth, but he very quickly drops it when Derek comes in, face going bright red.

“I thought you knew,” Stiles says quickly. “Well, until last week when you said you didn’t even notice my cats because you filter that out, so I realized you didn’t know, and then I just didn’t know how to tell you. Scott told me you hadn’t figured it out, but I thought you knew and just weren’t talking about it because you were embarrassed by it or something.”

Derek frowns. “Why would I be embarrassed that you’re a…” He doesn’t actually know what Stiles is. Every werecat that he’s known has been a big cat. Not a -

“Were-domestic housecat?” Stiles offers, dry. “No, I’m still technically a werecat, just not a big one. I think in shifter slang, we’re familiars - that’s what Mom always said we were, anyway. But I don’t know if that’s only a thing if you’re a werecat with a witch or what.”

“I still don’t know why I would be embarrassed.”

Stiles shrugs. “‘Cause I’m not, like, a big scary wolf. I mean, don’t get me wrong, I am the most efficient predator on the planet, and I would like it on the record that domestic cats are still apex predators.”

“None of this is any reason for me to be embarrassed by you,” Derek says, confused.

“I weigh like seven pounds in my shift,” Stiles goes on, like it’s obvious. “I’m cute and cuddly, and old ladies try to pick me up and take me home if I’m not careful so I usually end up in a tree and have to figure out how to get down. If someone manages to get me in a bag or has a laser pointer in their pocket, I’m pretty useless.”

“You’re so wrong that I don’t even know how to start telling you how wrong you are.” Derek finally moves forward, settles onto the bed next to Stiles. “I can list all of the amazing things you’ve done for us and in general, but we’ll be here all day. Besides, have you ever been scratched by a cat? Aim it right and you’ll be able to do just as much damage as I can.”

After a moment, Stiles makes a sound that might be something like agreement, even if he’s carefully watching Derek like he’s expecting him to burst into hysterical laughter at any second. “My dad has a scar from when he scared me once when I was thirteen,” he admits, and glances down at his lap, picking at the hem of the t-shirt like he’s fighting not to put it in his mouth. “And I can do that small spaces thing. With the-the cage and the keys.”

“I do have a question.”

The serious quality to Derek’s voice makes Stiles still and look up. 

“Can you purr? Like this.” Derek gestures at Stiles’ very human form, and knows that he’s losing a fighting battle of trying to keep a straight face. “If I play with your hair or something, will you purr? I can growl.”

Stiles gives him a look that can only be described as a ridiculously fond glare. “I’m not going to confirm or deny. Good luck figuring it out yourself.” Derek opens his mouth again. “Aaah! Scott made the ‘sex kitten’ joke months ago, don’t even.”

“Okay, I won’t.” Derek is still grinning, though, and there’s no one else in the world that he can be this ridiculously silly with, he knows. So it feels pretty good to be able to say, “So at Sunday dinner, can I tell your dad that the cat’s out of the bag?”

Stiles groans.