Pillowy Mounds

by Archy

Rating: mature
Tags: Original Character, Fetish, Random, Slice of Life, My Little Pony: Friendship is Magic, Anthro
Length: 7015

Uplift Gym is always after new snacks for its patrons, although this one might be more than they bargained for.

It was late at night, Felicity should have been home some hours ago but here she was, talking to her supplier about a new product. Something else to make her clients big no doubt, but what was going to be pushed her way this time? Her mind wandered too, with Mags unavailable, who would be able to test it? Her sister, Monday? Perhaps...

Commission for ThreeAreEss.

Please note this story contains fats, weight gain and blob sizes.

Cover art from Somefrigginnerd.

Published 2023-10-11 16:30:01 UTC
Last updated 2023-10-11 16:30:01 UTC

Pillowy Mounds

‘Come on Felicity, this is a special offer. Just for you, you’re my number one client for this sorta stuff, how can you turn it down!’

It was late, the Uplift gym had closed and customers had gone home well over an hour ago. Felicity seemed to remember she had waved off the last of them to leave with a smile. As the call she was currently stuck on had gone on, the smile had faded to a neutral expression. It was now most definitely a frown as she sat in front of her laptop in her office. The glare from the screen was making her squint. She turned on a light, the figure on the monitor became much more clear.

His name was Bulk Delivery, because that was what the stallion did, sell items in huge quantities. The gym equipment had been supplied by him. Everything from the yoga balls to the mats. He even did the machines that supplied the special milkshakes to the gym goers. Everything Uplift specific though? That was down to Felicity and Mags, although Mags rarely stopped by the gym herself. She had other things that kept her busy. Felicity was quite content to just let her try the expansive products when something new came in, which she always enjoyed a great deal. Right now, that was what Bulk was trying to push, a new product in the range they had developed. ‘It’ll come complete with all the Uplift branding you could desire!’ he said excitedly. He was really going for the hard sale.

Perhaps it was because Felicity was tired, or bored, or a mixture of both but she rolled her eyes and gave in. ‘But it’s just junk food Bulk, I know we do the shakes but that at least somewhat fits in with the gym theme of this place’ she said. ‘Alright, the gym is a bit of a misnomer, making ponies bigger rather than smaller, but that’s how we operate. They use the proper equipment to slim down, then I get them on the Uplift stuff to blimp up. Rinse and repeat. What’s the point of a customer who gets thin and leaves? No repeat business.’

Uplift Gym had a bit of a reputation in Ponyville for being…different to your average gym. Mags and Felicity had gone into it as partners, Felicity though had gotten the bright idea.

‘You know what the problem with gyms is?’

‘No?’

‘Customer joins, slims down, leaves. It’s only the ones who can’t resist a good meal too often who come back. Pretty low return rate right? Like maybe ten percent of ponies.’

‘Well what are you suggesting, we sabotage all the equipment?’ Mags had quipped. When Felicity’s expression hadn’t changed, her mood changed from jovial to serious. ‘You’re going to sabotage all the equipment?’

‘No, better and not quite so underhanded. We’re going to sell products that do away with all that good work. Shakes, cookies, stuff that’s loaded with fattening contents. Say to them “Well done with all that hard work, why not treat yourself?” hmm?’ she had suggested. It had gone from there really. Both of them had started to look into and invest into the stuff. It had been quite difficult to procure. There were plenty of excellent bakers throughout Equestria, but ones willing to load up their goods with quite so much of a fattening mix? It was where Bulk Delivery had come in. He was a little shifty, but it was what was needed to make the magic happen. Boy oh boy, did he make the magic happen. Mag’s own expansion magic was good, but she wasn’t a baker. Whatever contacts Bulk Delivery had, they had incredible magic that was poured into already stuffed shakes and goodies that made any pony instantly gain back all that weight they had lost (and more). It felt good too. The gym goers often came just for that sweet, sweet sip of a shake or bite of a cookie to feel their bodies instantly bulk up again. It worked, perhaps a little too well.

Right now, Bulk Delivery on the other end of a video call was waving a bag of the latest concoction to try to entice Felicity. ‘All your food is junk food Felicity. You can dress a milkshake or a cookie up any way you like, put bells and whistles on them, heck paint them pink and label it as “Extra Slimming” but all your clients know what it really does. This is another one of those junk foods.’ Bulk said with a sly grin. He waved the small bag in front of him one more time, pulling one of the small, white and soft items out from the inside. ‘You can’t tell me your customers won’t like marshmallows.’

Felicity leaned in closer to the screen, eyeing the small thing and inspecting it as best she could over a poor net connection that meant the resolution was low. It looked harmless enough. There was nothing to suggest the small morsel was anything dangerous. She knew otherwise though. ‘I’m still not convinced.’

‘Alright alright, geez.’ Bulk looked exasperated. ‘I dunno, you come up with great new products for your best customer and this is the thanks I get…’ he could see his hurt feelings act wasn’t getting him anywhere. ‘Fine. I’ll send you one bag to test, give it to any of your clients. I don’t care. Just make sure you can observe the results. When you see what it can do, you’ll be begging me to order a whole cartload.’ he said confidently. ‘Whadda ya say?’

‘Alright, mail me a bag.’ Felicity said, she wasn’t going to turn down a freebie.

‘I’ll get it out to you in the morning. Any pony comes to mind for the test?’ he grinned again. It was unsettling, the evilness behind it made Felicity feel slightly uncomfortable. Bulk hadn’t led her wrong yet though. She wondered what would happen if she stopped buying his products.

‘Yeah actually.’

‘Who?’

‘My sister.’

‘Dang, didn’t think you’d pick a family member. She into this stuff?’

‘No. That’s the fun part.’ Felicity grinned herself. It was reciprocated.

‘I see. Now that you got that on the way, how about the other orders? More shakes?’

‘Always more shakes.’ Felicity said, smiling. Hopefully this would be over soon and she could head home. The call was more of a courtesy to Bulk anyway. All this ordering could be done online. Sometimes though, it was easier to talk.

It had been only a day. The Equestrian Mail Service didn’t hang around. Resting on the doormat having arrived through the letterbox was an inconspicuous looking envelope. Felicity picked it up, it had Bulk’s company markings on. She was reminded of the conversation and put the envelope on the coffee table. If it looked inconspicuous it would be, the best way to hide things was always in plain sight.

‘Mornin’. She hadn’t heard Blue Monday come downstairs. Her ears had tuned out the usual drama of having to haul herself out of bed and get up at “Silly O’clock” as Monday liked to call it - Felicity being so focused on the envelope and putting it down in plain sight. Why she was up this early was a bit of a mystery to Felicity, who knew she only tended to get out of bed prior to the clock hitting double digits for a good reason. Maybe she had something on that she hadn’t mentioned yesterday?

‘You’re up early.’ Felicity walked over and joined her next to the coffee pot, the scent of the brew already creeping up her nostrils and reminding her that a caffeine kick was needed to start the day right. Monday tended to agree with this sentiment, as she poured herself a rather large mug and sat down around the island kitchen counter with it, taking a sip. She wasn’t a morning pony and it was the only way to get her motor running.

‘Mmm.’ was all she said, taking another sip. She didn’t seem to want to divulge what it was that she had gotten up for. Her coffee had barely been touched, still plenty in the mug. Felicity went to sit next to her at the counter, but made a small detail to the package, placing it next to her on the table. ‘What’s that?’

‘You know I am not sure.’ Felicity said, she covered the logo of Bulk’s company with her hand. ‘Bit of a mystery actually.’ she said casually tearing open the package. What spilled out was the same bag of marshmallows that Bulk had been waving at her. She had lied of course, expecting this to be exactly what was inside. She wanted to pique Monday’s curiosity. It didn’t work.

‘Marshmallows? Really?’ her sister asked, taking another swig of coffee. ‘That for the gym?’

‘Didn’t order any.’ technically this was the truth, she hadn’t placed an order yet. These were free samples. ‘Usually they let me know if they’re sending something.’ not the truth at all, a flat out lie.

‘Man I haven’t had marshmallows since we used to go camping as foals, remember?’ Monday said, she was eyeing up the small white treats for a second. Felicity wondered if she wouldn’t even have to get her interested, but then she snorted and laughed. ‘We were such dorks.’

‘Yeah, dorks.’ Felicity said. ‘Never mind.’ she tucked the marshmallows away for now. She’d have to be a bit more clever if she wanted Monday to test them. Her sister had become a little wary of anything Felicity proffered her way, especially if it was something for the Uplift gym. She flat out refused anything since that incident with what had been labeled as the “One tonne cookie” where Bulk had forgotten to add the zero after the one. There was always magic to cheat a pony back to regular size, but Monday hadn’t forgotten it. She’d give it another day or two, then see if she could figure out a smarter way to get Monday to eat them. For now she let it slide. ‘So, where are you going?’

‘Just got some chores to do.’ Monday said, finishing up her drink, getting up and putting the mug in the sink (not washing it of course). ‘I’ve got a gig to go to tonight so I want to get some things done in town this morning.’

‘Right, well I’m off to the gym shortly.’ Felicity replied. ‘Got a new product line out today, me and Mags have been rigorously testing some of the new clothing. It holds up pretty good.’

‘Just don’t come home in the back of a cart again.’ Monday rolled her eyes. ‘I’m not helping roll you inside the house if it all backfires.’

‘It won’t. I told you we tested it.’ Felicity tried to say, but stammered a little. ‘W-Well, after you know, some mishaps.’

‘I’m sure. That what the huge bill to rebuild one of the gym walls was for?’

‘Perhaps. Mags did that though.’ Felicity said, trying to pass the buck for the incident.

‘You can’t blame that pony for everything.’ Monday said, grabbing a coat and opening the front door. She often went out lightly dressed, but today was chilly, she had at least decided to grab something that would keep her warm. ‘Later sis.’ the door shut, leaving Felicity alone in the house.

Felicity could feel her hand tighten around the coffee cup as she finished her own drink. She didn’t blame Mags for everything. Okay, sometimes when things happened, it might have been the both of them and she made it look a little as if Mags had concocted the idea, but this time it was her giant ass that had caused the wall to come crashing down, not Felicity’s.

She washed up, her mind already racing about ideas to get Monday to down every single marshmallow in that packet. Before she had left the house, one had clicked. It was perfect.

The next day was almost a repeat of the previous, just much later in the afternoon. It was a Saturday. Gigs always meant drinking too, so Monday didn’t emerge until well past noon. Felicity was somewhat banking on her groggy state, although taking advantage in this way was somewhat cruel. She had to at least try to sober up Monday first.

‘Here.’ she passed her a coffee. Monday took it without hesitation and began to drink. Slowly she seemed to become a bit more compos mentis. ‘Good gig?’

‘What, can’t you tell?’ Monday replied. ‘I thought the state of me would have been a bit of a giveaway.’

‘It is, I just like to make conversation sis.’
‘It’s too early.’
‘It’s gone twelve.’

‘Too early.’ she repeated, taking another sip of coffee. There was silence for a moment. Felicity then pulled out the marshmallows from the drawer she had secreted them in yesterday.

‘Did some digging into these.’ she said, opening the packet up and putting a couple on the table. ‘You were right, they’re for the gym.’

‘Knew it.’ Monday said, dismissively. ‘Another “snack” for your patrons to indulge in to add several thousands of pounds to their frame?’ Monday said, she was perking up.

‘Actually no.’ Felicity said. ‘The opposite, it’s like a quick-loss snack. As good an idea as it is, it’s not quick to lose all that weight.’ Felicity explained. ‘Having to order a whole heap of carts to haul ponies home after a workout session isn’t exactly ideal. I mentioned it to one of my suppliers. This is what they’ve come up with.’

‘Right, so they get big, then eat one of these, then go back to normal size?’

‘Pretty much.’

‘They’ll stop coming for workout sessions.’ Monday quipped.

‘Some sure, but a lot of them enjoy using it to put those big bodies to the test. I don’t think they’ll all go for it. The option is there though, at least.’ Felicity replied. She pushed a marshmallow towards Monday. ‘It won’t do anything if you’re already thin though, I’ve had one. Just wanted to get another pony's opinion on the taste.’

‘It’s a marshmallow. It’s going to be soft and sweet, and likely melty if I put it in my coffee.’ Monday said, pushing it back towards Felicity. ‘Can’t you ask Mags?’

‘Not at the moment, she’s showcasing the new stretchy clothing line and needs to keep her bulk.’ Felicity explained. ‘Look, I swear nothing will happen.’

‘Better not.’ Monday said. She took the marshmallow and inspected it closely, holding the thing a few inches from her eyes and then lowering it down to her nose, sniffing it. ‘Smells like a marshmallow anyway.’ she popped it in her mouth and began to chew, washing it down with a gulp of coffee.

It was a double bluff. Tell her the food was for the gym to prove Monday right, but completely lie about what it did. The thing was, Felicity knew this was only going to be a one time tale she could tell about any foodstuffs that arrived at the house. Whatever its purpose was, Monday would never believe her again.

‘Taste’s pretty good.’ Monday said, chewing on the remains she hadn’t swallowed down. ‘Maybe a bit too sweet, but you know me, I’m not really one for sweet things.’

‘Yeah I know, well at least it’s something I can feed back to the supplier.’ Felicity said. ‘I found them pretty good, but perhaps we can go for a less potent variety.’ Felicity said with a grin. Monday squinted her eyes.

‘That’s a strange word to use to describe taste. Usually that applies to…’ Monday started to say. She felt something tighten, it was the bra she was wearing. Two girls living together meant she was pretty lax with clothing when she had just gotten up, putting on little more than something to cover her most private areas. ‘You lied to me.’

‘Call it stretching the truth.’ Felicity said. She watched as Monday immediately frowned, she’d have gotten up and started ranting at Felicity, but she was too enthralled at what was happening to her body. That tightness on her bra was only getting more noticeable as her breasts began to try to squeeze their way out of the confines of the material. She was starting to swell up. Not just her boobs, but her ass, belly and thighs were all beginning to pack on pounds as the magic and calorie loaded marshmallow began to work inside her. Felicity watched as her older sister practically swelled up, her body rapidly expanding to an incredible size that would shortly be unable to be contained within the bra and panties (black, of course) that Monday had thrown on when she got out of bed. Felicity giggled. ‘Although I think you’re stretching that clothing pretty well.’

‘SCREW you. I can’t believe I went for that, thinning foods my FAT TITS.’ Monday bellowed. She had doubled in size already, but still quite mobile. With some effort she pulled herself up from her chair and began to make her way towards Felicity, before the excessive weight of her expanding breasts pulled her forward, sending her straight onto that expanding belly. She hit the floor with a whump and groaned. Thankfully, the marshmallow filling her up acted somewhat like a cushion, making the mare hit the ground lightly. ‘I will get you.’ she grumbled, struggling to pull herself up from her new position.

‘Celestia, let me help you at least from that. It’s not very flattering.’ Felicity said, rolling her eyes and summoning what strength she had to pull her sister up from the floor. She was upright again, standing with her arms at her side, displaying a typical “I am not happy.” stance that Felicity knew all too well. She relaxed them though, the anger slightly taking a back seat to lust as the mare noticed what the marshmallow was working to achieve.

Curves like she had never experienced were forming, the shape of her body changing to accentuate all those wonderful things that she enjoyed as they had been, but now were being amplified. The only outlier was her belly was forming into a rather big ball, seeing as that’s where the marshmallow had ended up, but it gave a rather nice support to those massive breasts that she cupped with her hands. The bra had somehow, still survived and was only adding to that feeling of tautness. She wiggled her hips, feeling the same with panties that were made for an ass twice as small. She pouted, she didn’t want to give Felicity any sort of impression that this was enjoyable for her on any level.

‘I’ve tried some of your products before, they never worked this fast.’ she said, still observing her body and feeling around for where she was getting bigger. It seemed to be everywhere. ‘The heck is in these things?’

‘Magic and well…I don’t know.’ Felicity had to admit. ‘I had a call with Bulk, he wasn’t exactly specific about what they contained. He just told me what they did.’

‘Of course, Buck. He’s the one who got me into this sort of mess last time.’ Monday said, her growing breasts wobbling as her body wobbled around while she spoke. It was getting harder and harder to make no motion at all, even the slightest little sway of those hips caused things to jiggle. ‘Whatever ponies are making these have some crazy baking skills and magic.’ Monday conceded.

‘Well, it’s doing all the right things.’ Felicity said, stepping closer. ‘I mean look at you, curves that could knock any man dead.’ she giggled. ‘Although probably just turning around and hitting him with those breasts or that ass would do the same.’

‘P-Please.’ it was the first stutter from Monday. ‘How long is this gonna keep going?’

‘I really have no idea.’ Felicity said, suddenly thinking about the house. Monday was stood in the living room and starting to fill it rather fast. As much fun as destroying property was, what with the gym having taken damage recently and all, Felicity didn’t really want another big bill on her hands that she’d struggle to pay for. She could only really raise gym membership prices so much. She grabbed her sister's hand. ‘Better get you outside before you start to wreck things.’ she began to pull, but Monday, with her new found size, resisted it quite easily.

‘The front!? Are you crazy?’ she huffed, pressing her weight down on Felicity in response, pinning her up against the wall. ‘Everyone will see me and stare, for a start.’

‘Alright…yard?’ Felicity pleaded. She could feel the weight of her growing sister really smooshing that expanding flab into her. Stomach and breasts pressing tightly against her body as the wall started to fail to resist the weight. Thankfully, Monday pulled away before she leaned on it so much it collapsed.

‘Yard.’ she said. ‘And this better stop before I get really huge.’

‘It might.’ Felicity said. It was a rather flippant comment. She really had no clue.

‘Oh come ON, I’m not that big!’

Her sister's protests bounced off frustrated ears. She was that big, big enough that in the short time Felicity had tried grabbing her to pull her out to the backyard her stomach had already ballooned so wide she was struggling to get out the door. Her belly had made it out…halfway. Her hips had then gotten stuck on the doorframe that Felicity was trying to push her out of. She was thinking about going to get some lubricant. Butter, perhaps? But apparently there wasn’t any need.

CRACK!

Wood splintered, long dried flecks of paint flicked up and flew off in all directions. The door frame was done for, completely unable to withstand the force of the expanding Monday who once more, fell forward out of the now broken frame and towards the grass. She had learned from the first experience however, catching herself as she started to tip but correcting with all the strength she had and pulled herself straight. Felicity grabbed her, making sure she didn’t fall on her ass instead, as funny as that would have been.

‘Okay, forget about the door frame. I’ll patch that up later. You’re outside, the house is safe.’ Felicity said, trying to reassure her somewhat.

‘That’s what you think. I know what your Uplift snacks are like.’ Monday started to pout, she stood, hands balled into a fist at the side of her hips as she prepared to give Felicity a bit of a lecture. ‘This is just the start. I’ll keep growing, I won’t stop, you’ll find some way to cram the remaining packet of marshmallows in my mouth when I can’t protest about it!’ she waved her arms around, which were now noticeably thicker as well.

Felicity hadn’t even considered giving her more, at least not until Monday had mentioned it. She’d see how Monday did just on this one marshmallow. She was still expanding.

‘Well, at least tell me how it’s feeling.’ Felicity replied, as Monday drew some exasperated breaths from her shouting. ‘Now we’re in this situation might as well figure out if the snacks are worth stocking at the gym.’

Monday just frowned, giving her an “Are you kidding me?” look. There was a quiet blourp as her stomach swelled out another few inches. Eventually she just rolled her eyes and relented. ‘Honestly, the thing I’ve noticed is that I’m not getting any heavier, despite my size.’ she gave her stomach a small pat to emphasize the point, it made another blourp.

‘Really? You don’t feel any weightier?’ Felicity asked. She took a few steps closer. There was no denying that Monday absolutely was bigger. She had ballooned. What Felicity would call all the usual good stuff that went with this sort of thing. Ass fighting against her panties, stomach would be making any clothing ride upwards if she had a shirt on, but right now the bra sat positioned rather nicely on her billowing breasts. It was what her customers would enjoy, that sort of change to their figures. Her mind began to wander as she thought it would make a good alternative, they could actually walk home. As long as they retained the ability to walk at least. Some complained about the sudden added weight. This seemed like a good alternative to any foods that might suddenly make them heavy. Her mind wandering was snapped back to the present situation by Monday clicking her fingers and waving her hands in front of Felicity’s face.

‘Hellooooooo? You go off in your head again?’

‘Only for a second. No added weight huh? Just all the bulk.’

‘Yeah, that’s what I said.’

‘Hmmm.’ Felicity observed her figure was settling. ‘You know what I’m going to ask.’

‘If I’ll willingly eat the rest of the marshmallows in the packet so you can figure out what more of them do if any of your clients eat more than just a single one?’ Monday said extremely sarcastically. She then ramped it up. ‘Sure, stuff me with all the rest of the marshmallows. Make me a house blimp, forget about the fact I don’t really mff ff mfff fmmm mffff?-’ she would have finished, but Felicity put a marshmallow between her lips, which was quickly chewed at the same time as her words. When she swallowed it, there was another deep frown. ‘I hate you.’

‘And I love you.’ Felicity smiled back, giving her sister a little pat on the head. She was keen to see if another one would have any further effects. Some foods had a certain limit, no matter how many you ate it wouldn’t make you grow anymore. The marshmallows however absolutely did not fit into that category.

Immediately the second one started to have an effect quickly, even more so than the first. The swelling was somewhat noticeable with the first one, but a little on the slow side despite Monday’s protests. Now it was rather more obvious, with her body getting bigger once more. Despite the fact there was no weight to hold up, Monday leaned forward on the yoga ball-like belly, using it as something to lean on as she just started at it and her breasts ballooning bigger. She flicked at her side, hitting the clasp on the panties, sending them shooting off her ass rather than waiting for them to pop off on their own. They ended up somewhere in a tree, flung with force from her waistline.

‘Huh.’ Monday gave her stomach a small prod. Not to see how it was growing, but she had noticed something else. ‘You might need to tell Bulk there’s a side effect to these things.’

Felicity looked at where Monday was pointing. She squinted her eyes, it was a little difficult to make out, but her stomach was definitely turning a lighter colour shade. Monday was quite a dark blue all over her body, this was certainly changing but very slowly. It was actually making her skin tone more in line with Felicity’s, which was a lighter blue. ‘I’m sure it’s reversible when the effects wear off.’ Felicity smiled. The sort of fake “I totally know what I am saying.” absolute lie that comes with any false truth. Monday just exhaled.

‘Sure.’ she sat herself down, it was becoming a bit difficult to actually stand. Her stomach now pushed out so far in front of her it was actually starting to force her backwards. At least she had a very large, growing cushion to sit down on which came to rest easily on the grass behind it. She put her arms up, leaning over her breasts to see how far forward she could reach now. Her nipples were just about grabbable, but these also soon forced themselves far enough away she could quite get at them anymore. She had about doubled in size from her previous resting position. It seemed the marshmallows made you grow roughly double from your current size. Felicity wondered if this might be exponential. ‘You know our fences aren’t very high, if you keep giving me more, this isn’t going to be very private.’ Monday grumbled.

‘You’re a giant, nearly naked blue ball.’ Felicity giggled. ‘Of course ponies are going to stare.’

‘...Couldn’t have rented out a big hall or somethin’...’

‘You’d have never agreed to it.’

‘Of course I wouldn’t have. I’m not an idiot.’ Monday replied, then just rolled her eyes again. It was a tell-tale sign she wasn’t pleased. ‘Is there another one of these damn things coming my way or not?’

‘Well, I dunno - you’re being kind of rude to me about it.’ Felicity said, she held the bag and contemplated if she really wanted to pass her sister another one of them. She could tell despite all the protests, Monday was enjoying herself. It was her way of faking interest, the more she protested the more she wanted. She had always been this way. The stutter earlier had been a good indicator too. More of those were likely to come.

‘Just give it to me.’ Monday huffed, her large body resting once more at the much bigger size. ‘You want a proper test, don’t you?’

‘Of course. Open up.’

‘I’m not a baby.’ Monday said, snatching the next marshmallow from Felicity before she could feed it to her. ‘I can eat the whole..mfff damnf packfetf myshelf!’ her last words were a little laboured, as she spoke through greedy chews.

‘Want me to just leave it on your tits?’ Felicity teased.

‘Get lost.’ was the retort. Felicity laughed.

It was the last marshmallow. Monday had dropped it trying to wiggle her fattened arms towards her mouth. It rolled down her triple chinned neck, gathering enough speed to make it up and over the peak of her cow-sized breasts and then down the large, extremely spherical belly that now filled most of the garden. She burbled a little from her mouth, looking at the marshmallow which had stopped near Felicity’s feet. She picked it up, five second rule after all.

Over the course of the last few hours, she had managed to quite greedily chomp and chew away at the roughly fifteen marshmallows that remained in the bag. It had allowed Felicity to observe fully the effects of the food. Some of it she had expected, some of it was a total surprise.

The parts that were expected? Well there was the incredible size Monday had grown to. That was very expected after the first two. Might have been the biggest she had gotten yet trying any of these snacks Felicity had put her way. The bra had given up quite a while ago now. Felicity estimated that one of Monday’s areola was bigger than the entire of Felicity’s head. Her stomach had rapidly swelled into a massive ball, big enough to take up most of the space of their sizable back yard. It was roughly two thirds covered by stomach, then the rest covered up by two impossibly bloated ass cheeks. They were pressing up against the fence. The wood fence panels protested but only leaned backwards slightly. None had splintered…yet. This was topped off by breasts where each one was the size of a small cart and arms and legs that had lost any form of mobility long ago. If Monday had wings, they would have been useless. There was a distinct lack of magic too, seeing as she had no horn. No way to get that marshmallow back that had dropped down to her sister. “House sized” was the best way to describe her form, not blocky by any means, round and as big as one for sure. Her body bobbed slightly in the light breeze that blew through the yard.

Now what was unexpected? The speed at which this had all happened was quite surprising to Felicity. Usually any snacks took a day or two after consumption to work their way through the eater's body and get to work. Not these little white wonders, they began to get going even while being chewed. The other part that was surprising was well…the colour change. Her skin all over had gone off-white, as if to resemble a marshmallow itself. Some parts were darker, but it all fitted together quite neatly. Monday hadn’t mentioned it, Felicity had just made a mental note to warn any pony who ate a large number of them in one sitting that this could potentially be a side effect. It was certainly quite obvious, apart from Monday’s hair and tail, most of her was now white. Eat enough of them it seemed and you became marshmallow yourself.

It was a wonder so far none of the neighbours had seen from the surrounding houses. The backyard was off the street, so unless some pony particularly went snooping Monday could grow, gurgle and blorp in peace. It was also still more towards the early part of the day. Felicity began to wonder if Monday would slim back down just as quickly as she had blimped up, but her body had come to a stop. She turned the final marshmallow over in her hands, wondering if this one might just be a single snack too far. ‘You want to finish the job?’ she asked her sister.

There was a grrrummmbblllleee from Monday’s expansive stomach. It seemed to answer the question for her. Felicity just smiled, fluttering her wings to bring her up to rest on her sister's stomach. It was like landing on an extremely large balloon. Taught and supportive, but extremely soft at the same time. It actually felt like walking on a very large water bed more than a balloon, it just didn’t have the weight behind it that water would provide. She nestled herself between Monday’s breasts, almost teasing her with the final treat. ‘You know all these protests, and you’re an even bigger glutton for this sort of thing than I am.’ Felicity giggled. ‘Are you sure you don’t want to be part of the Uplift team? Mags does her fair share of taste testing, but we could use an official one. You’d be perfect.’ Felicity proposed.

‘Just give me the d-damn…uuuRRRRrrrPPPPppp…marshmallow.’ she said.

‘As you wish.’ Felicity didn’t hesitate, and popped it in her mouth.

There were a few moments of chewing before the entire marshmallow was swallowed, nothing happened straight away as before. Felicity worried Monday had reached “peak growth”. Every pony had their limit after all, no matter how much the food being eaten might want to push their body to expand.

This didn’t turn out to be the case though, Monday was just stifling a belch, apparently preventing further growth until she let rip.

‘BBBWwwwAAAaAAaaaaAAARRRpppPPPPPP!!!!!’ If the neighbours hadn’t heard the commotion yet, they will have now. A glass shattering belch erupted from the now white Monday and made Felicity cover her ears. A few panes of glass on their house cracked towards the back. Monday just grinned. ‘Your paying for that.’

‘Fine, it’s the least I can…woah!’ Felicity had to grab onto something, Monday’s body shifted underneath her. Her stomach lurched forward, the expansion taking hold as her body swelled up and puffed full of more fat. Felicity gripped onto a cart sized breast, which was growing into a couple of carts quite quickly. It bobbed around but provided a good anchor to get a grip on. She waited until the surge had passed, then let go. The expansion carried on, but it seemed the sudden jolt into it had passed. Monday’s stomach blorped and glorped. It was doing its best to cope with being so huge, it was by far the biggest part of her. It shadowed everything else. ‘You know I think we’re starting to run out of garden…’

CRUNCH!

‘...space.’ She knew that the fence behind Monday wasn’t going to last much longer. It gave way right on cue. ‘Hopefully the neighbours aren’t home.’ Felicity said, rolling her eyes. She didn’t want to explain how the prize petunias had been crushed by an ass the size of a haystack, again. Hopefully they could sort it all out and get things back to normal before ponies got home.

Monday didn’t say anything. She just grinned. They were hardly going to blame her, were they? She hoped she kept growing, destroyed their house, garden, drive…everything. Felicity could explain how she had asked her sister if she could do her a favour, that it was all her fault. Besides, Felicity was right, unfortunately. Monday did enjoy the growth. Felicity knew she enjoyed the growth, but would Monday say it outright? Not in a thousand years. It was completely unspoken and Monday liked to keep it that way. Right now, she was just revelling in how this all made her feel. Everything being so big and so large was something else entirely. Felicity had before had her try things, they all did something to varying degrees. The best one up until this point had been a cookie which set your body to an hourglass shape and bloated it up to make you weigh just shy of a thousand pounds. Most things though you ate one of and any further treats did nothing more. These marshmallows though? They were absolutely something else. A snack that kept making you bigger the more you ate? Monday wondered what a cart load of them would do.

The overall feeling however was extremely hard to describe. Her body felt big. Really, really big. She was big, the biggest she’d ever been. But to feel it to such a degree? There was something about this whole thing that made her heart dance and her body feel electrically excited. There was a sensation of power behind it all, one that grew with her. The bigger she was getting the more of it she wanted. Perhaps it was something the marshmallows, or something else entirely. Monday couldn’t be sure. She just knew that once the final one she had eaten stopped making her grow, she’d be seeking out more of them. Hopefully Felicity was satisfied enough with the results she’d be stocking them in the gym. Monday was sure a few (dozen) packets were likely going to go missing after the first shipment. She’d have to consider some bigger clothes. Panties and a bra that didn’t give up, tight against this body? Oh now that would be another degree of heaven altogether. So many possibilities…

Glourp!

Her stomach stopped, just short of the other fence. It seemed the marshmallow had given all it could. Monday’s body continued to lightly bob up and down, helped along by Felicity who was still perched between her breasts. She hadn’t moved but she did now, fluttering her wings and hovering slightly above Monday who had absolutely no way of moving herself. Felicity couldn’t decide if she was more like a giant garden ornament, or just the garden itself - now covering most of it.

‘I believe that’s the most successful fattening snack Bulk has ever sent my way. Some real puffy marshmallows.’ she said, just watching to see if her sister had any more growing to do. She was definitely done, however.

‘I think I’m the puffy one, a-actually.’ Monday said.

‘The Stay Puft Marshmallow Mare.’ Felicity laughed. She saw a quick grin from her sister, but she quickly stifled it to try to remain stoic. Felicity just shook her head, the pretence she was keeping up was useless and rather pointless but she decided to humour her, at least for the sake of her feelings. ‘I’ll be honest, I don’t know how long it’s going to take for you to return to normal size. You kept eating them.’

‘M-Meh. It can take a week for all I can.’ Monday replied, head sinking a little into her bloated necks. ‘Y-You can explain to the neighbours about the fence, though.’

‘Fine. Yet another wrecked wall I’ve got to explain to some pony…’ Felicity said. She realised she was still holding the packet, now empty. She tossed it away. ‘So, should I order some?’

‘Yes.’

‘And you don’t want any.’

‘...’

‘...’

‘...Look if some make it to the house, I won’t complain.’ Monday said.

‘Alright.’ Felicity said with a small laugh. ‘Saves me finding the gym has missing stock.’

‘That’s not me, you should keep a better eye on your customers.’ Monday protested.

‘Sure.’ Felicity parked herself a bit further down, on the gloorrrpp’ing belly of Monday. Despite the fact her sister had stopped growing, it was still churning away at whatever was contained within. Perhaps the marshmallows expanded inside the pony eating them? Causing all this growth? She didn’t really care to find out. The snacks were incredibly potent. They’d need to come with several warnings, as well as training the staff to ensure any pony eating them was well, well outside the building before they did. This was of course, assuming they ate a whole packet, not just one.

‘You know I didn’t think it would make me this big.’ Monday said, still a little impressed by it all. That wasn’t something she could hide.

‘No, me either.’ Felicity said, giving her sister's enormous belly a pat. ‘I’ll leave you to slim down. Shout me if you want a blanket or…well, that’s going to be like a napkin on you. Uhhh…’ Felicity thought for a moment. ‘Look I’ll get Mags to magic something big enough to cover you up if you’re still out here and this big this evening, ‘kay?’ Felicity asked.

‘Kay.’ Monday said. There wasn’t really much more Felicity could do, so she just nodded to let her know she’d be fine on her own for a while. She tried wobbling her frame, but it was a little difficult to do so. Felt good though. She hoped she’d be out here like this a while longer. Just to experience it, every moment she remained this size was bliss.