Imagine: Filled Out Kitty
What's ahead: an extended weight gain/tf imagine story about the fattening that results when the protag's witch roommate accidentally transforms them into a house cat.
Imagine you become roommates with a timid-seeming girl who practices witchcraft. You don't think much of it at first since she's an exemplary roommate otherwise, until you end up inadvertently consuming one of her potions from out of the fridge (perhaps mistaking it for a regular milkshake). The next morning you wake up in your bed feeling strange--and you realize you've been transformed into a cat!
After taking a moment to get used to your new bearings you go and meow incessantly at the door to your roommate's room, knowing immediately that she's the reason this has happened. After quite a bit of confusion and struggle, you are able to get her to realize what has happened, and she's rightly horrified. She explains that the potion you drank was experimental, that she had no clue it would do this and she unfortunately has no clue how to turn you back.
So, you're stuck as a cat for the time being. You're rightly annoyed by this, but you quickly begin to realize the many benefits to being a cat. You get to laze around and nap all day, and it feels so much better to do so when covered in fur. Your old surroundings suddenly feel new again in your new form, full of chances for exploration. There's also, well...the food.
Your roommate, out of both guilt at what she'd done and inexperience with taking care of cats, ends up feeding you more or less to your heart's content. For some reason you don't register exactly how much food you should be eating at your new size, and so you accept as however much you're given (although she does make sure to exclude food toxic to cats). Eating human food as a cat also feels all the more indulgent somehow.
Of course, these eating habits almost immediately leads to you beginning to pile the pounds onto your now much smaller frame. It's hard to notice at first underneath all the fluff, however. This initial added jiggle makes you all the more comfortable to pet, something your roommate starts to enjoy more and more. At first you found it awkward, until you realized being stroked was quite enjoyable. Soon you were purring as she stroked your growing belly after every meal.
Your roommate also continues to furiously research a reversal to your condition. She constantly updates you on her progress, although you find yourself caring less and less about the prospect of becoming human again. However, you are hit with a shock one day when she confronts you as you laze on a windowsill. She says sadly that she's deduced from her research that the longer you stay a cat, the more you will mentally become one. This explains why you've become more and more content with lying in sunbeams and eating all day, but you're still present enough to be shocked by the news.
This information almost seems to send your roommate's sense of guilt into overdrive, so she plies you even more with food and sweets. You find yourself with an increasing appreciation for actual cat food, so she makes sure to supply you with the fanciest wet food at your every command.
You've started to round out intensely at this point, your belly bowing out and completely eliminating any suggestion of a waist you'd had previously. When standing your tummy sticks out obviously from your sides, and when sitting it pools as a furry mass between your legs. You begin to notice that it's harder and more painful to move around on your legs, but since you spend most of your days lounging you don't really care. Your roommate, for her part, seems to find you cuter for all the weight you've gained, and takes to calling you her "roly-poly kitty".
It isn't until your roommate happens to have a friend over (someone who doesn't know about your condition, since it's been months since you were turned) that your plight is finally discovered. At one point as the two sit and talk over coffee, you lumber in after your latest meal and walk up to the couch where your roommate sits. You lazily attempt to jump up onto it with her, but of course you're a bit too weighty to actually do so. You need only look up at your roommate in order for her to reach down to lift you onto the couch, eliciting a groan from both her and the couch in the process. Your lay there on your side like a sack of potatoes, belly splayed out before you.
"dude, your cat is FAT" your roommate's friend comments.
Your ears perk up slightly, but it's been a while since things like body image were of any concern to you.
"Oh I know, isn't it a cutie?" Your roommate asks, reaching out to jiggle your belly slightly (something you're very accustomed to by now).
"No, I mean like, REALLY fat. I don't think it's healthy."
"....Oh" Says your roommate, looking down at you with a frown.
You do not realize the significance of this exchange at the time, but later your roommate makes an attempt to explain that she's going to have to put you on a diet and start feeding you like a normal cat. You've no longer had much interest in concepts like "diets" and "normal" for a while now, but a memory does stir in you when you're met with only one measly can of wet food mixed with kibble for breakfast and dinner respectively.
Compared to the buffet you'd been used to for the past few months, this new "normal cat diet" leaves you feeling absolutely starved. You find yourself wailing and scratching at your roommates door for hours each day as your stomach screams out in emptiness. Usually you do manage to wheedle a few extra cans out of her, but still not enough to sate your burning hunger.
This hunger seems to accelerate your mind's transition into that of a cat, as it consumes all other thoughts in your brain. It comes to a head when your roommate goes out for the day after feeding you only one tiny bowl of food and a handful of treats. Within an hour you are howling with hunger, and your one-track mind leads you to the cupboard where your roommate keeps the kibble. In an uncharacteristic flash of human intelligence, you manage to get the cabinet open and push the bag out onto the floor, scattering food everywhere.
Hunger the only thing on your mind you begin to absolutely gorge yourself on the spilled kibble. You do this until you're full, only taking breaks to drink from your water bowl, and then pass out in a food coma before waking up to start the whole process over. By the time your roommate makes it home you're lying immobile on your back on the kitchen floor, having consumed the entire bag and only thrown up twice.
Your roommate is of course horrified when she gets home to find you a bloated mess. She kneels besides you rubbing your distended belly as she scolds you.
"I can't believe you really did that! hopefully you'll be ok... I guess I found the answer to reversing your spell just in time!" She says brightly, pulling a book out of her bag to show to you. You're too blissed out to respond with more than a weak meow as you fall back into sleep.
You wake up in your bed--someplace you actually haven't slept in a while--but something's strange. Everything feels heavy, but even more than usual. You slowly open your lids to realize with shock that you've been turned back into a human.
As you look at yourself you realize the true implications of your stuffing the past few months. The obesity of your cat body has translated into the obesity of your human body, complete with your huge rotund belly spread out between nearly useless appendages. Your cat-sized stuffing has also resulted in a human-sized bloat, giving your already large belly a domed-out look. Without a doubt none of the clothes in your wardrobe would even have a chance of fitting anymore. You look nothing like your former human self, having completely taken on the physical weight of your cat self, and you're still too mentally checked out to mind all that much. You reach out and begin to rub the top of your massive belly to soothe it, AND Finally you realize your roommate is standing at the edge of the bed waiting for you to wake up.
"I'm so sorry it happened this way..." She says, taking in your now massive body. "I promise I'll take care of you just like I did before, since it's my fault you ended up like this."
You rub your stomach thoughtfully for a second, then ask; "Will you come rub my tummy for me like you usually do? Some of it is hard for me to reach."
Her face breaks out in a huge smile, and she approaches you on the bed. "Of course I will. And in just a bit I'll make you something to eat as well. I bet you'll be happy to have human food again." Her hand lands comfortably on the lower part of your belly and rubs it just as tenderly as usual.
You nod, your new fleshy chins jiggling. To be honest, you're not really feeling picky as to what food it is, but you don't tell her that. "Yes I'd--uurp--Like that. I think I'll be hungry again soon."
Your stomach rumbles as if on cue, and she grins at you again. In another life you might have thought she'd somehow planned all of this on purpose, but in your current one you're too happy to care.