Big Surprise
Enjoy, this is my first fic on the matter.

It was a bright and shiny day in the afternoon of Ponyville, and all seemed good. Birds were singing, grass grew, and life seemed pretty good for the time. Today, it was the perfect day to go out for a pleasant stroll, as Celestia’s sun shone it's orange glow across the sky of Equestria, shining it’s radiant warmth across the land.

Walking across the meadow ever so tenderly was a grey timid mare with a dark grey mane that flowed over her forehead and hid one of her magenta-colored, innocent eyes. This mare, known as Marble Pie by the locals, slowly trotted across this green meadow without a worry in the world while sniffing at a daisy upon the ground, then proceeded to lick at it, scooping it into her mouth and proceeded to chew on said daisy essentially eating it as some sort of snack. All was well as the mare slowly and nonchalantly stumbled across the grassy hill heading downwards with ease, surely it wasn’t going to end bad…


Sure enough as Marble trotted carelessly, her hoof clipped against an industrial cylinder pipe of some sort which lead to some air tank, which caused her to trip and fall on her stomach with a grunt of pain. Groaning in discomfort, the grey mare stumbled to her hooves, turned around and looked upon the pipe that tripped her. Examining it closer, there appeared to be a red pressure valve onto one of the many notches it possessed.The mare knelt down to examine the shiny valve closer. Lifting a hoof, she then gently caressed the notches of the valve, unfamiliar with the device as she curiously prodded the knob, wondering where it went to clueless…big mistake.


Suddenly, the valve spun out as soon as she made contact with it, causing air to spew from the seams. The piping begun to bulge, and before Marble Pie could even react quick enough, the once parallel aluminum piping suddenly bent upwards at a 90 degree angle, just as the poor startled mare gasped in fright, squealing out in terror as the pipe sprung upward with her maw agape. Marble yelps were soon deafened by said air pipe lodging itself into her gasping mouth and begun to quickly expel this hot air into Marble’s shivering mouth hole, and down her throat inflating her stomach first gradually.


Unable to move now, Marble begun flailing her hooves about, as she squealed in horror, feeling her abdomen tighten gradually with each and every second of the evil pipe that intruded her esophagus, and even other parts of her body. Her gaze shifted to the pressure gauge, displaying the dial was all the way to the right being at full raw air pressure. It was uncertain how much PSI it had, but one thing was for sure is that the poor mare was inflating fast.
At this point the shy frightened mare panicked, while her puffy cheeks plumped up to their fullest, making her face look pudgy. Marble’s body continued to expand with each passing moment, moments seemed to become hours for her. Eventually her belly expanded to the point where it begun to puff out her limbs now, which includes her back legs first causing her thighs and hindquarters to expand to extraordinarily proportions, her plot cheeks expanding the most out of her four limbs, making it look plumper and more voluptuous to the untrained eye. Her expanded flanks even inflated so much to the point where her cutie mark had to compensate for the added area and stretched to fit. Then her forelegs formed into her ever expanding torso, all four of her limbs inflating to the point of seeming like little puffy nubs on the ends of her body.


The pressure gauge seemed to increase higher than it was supposed to go, even red-lining to the very bottom,which only inflated her body more rapidly, which added more buoyancy to weight ratio…the look of worry only grew on her face as her body only tightened further, becoming, not painful, just very uncomfortable for her as her skin stretched, her flesh stretching passed their limits with ease. Then, a different kind of pressure built up inside of her, causing her stomach to grumble and rumble in the middle of all of this.


It would appear that the daisy from earlier was not sitting right with her stomach which made itself apparently known via her stomach that churned and gurgled from the bad daisy...just remembering that she gets really gaseous when consumption of daisies occurres. The scared mare clenched her butt cheeks hard, in hopes that it wouldn't come out just yet. As a result this creating more discomfort for the poor mare. Marble begun to shudder if she could, still unable to free herself as she appeared completely immobile. Looking back at her body, her entire body seems to have been borderline blimp sized, as her size had to have been more than 90 to 120 inches in diameter.


Marble tried her best to hold back the pressure, feeling with each aching moment the pressure only grew stronger, and stronger as her tail begun twitching rapidly. However, the groaning in her stomach just grew louder, as the pain intensifies while her stomach continues to expand, slowly. The mare’s stomach was upset, which caused her to groan in pain, as the pressure got worse and worse with every second. That gurgling sound only got louder, as the pressure continued to grow inside of her, her body reaching lengths far surpassing it’s normal width while her body bobbing up and down like a big squishy balloon.


From behind,she could tell her own lower body begun rumbling, her eyes widening from the sensation, knowing all too well what that meant…the mare tried her very best to hold it back, but the pressure building up made this a difficult task which wouldn’t be so much of a problem, until she heard hoofsteps from behind. This is when she begun to become anxious, her eyes widening and her chest dipped.


Marble’s chest sunk, as she tried in vain to free herself from the wretched pipe, squeaking and squealing in efforts while bobbing her head up and down in hopes she would be freed in time, to no luck. The pressure inside was growing rapidly, and it was only a matter of time before she will be forced to give in to the pressure which would be less of a problem if she was by herself. However, this was not the case as the sounds of her sisters came into hearing range via the chattering, the giggles of her sibling throughout the meadow echoed through her head. Marble knew that she had to do something,though also knew that she could do nothing but wait for the inevitable, her plotcheeks rapidly grew and torso expanding slower and more firmly now to compensate for the pressure while her skin tightened and became shiny, straining and creaking with the pressure that was adding up inside her.


Limestone pie, Maud Pie and Pinkie Pie trotted close by, unaware of the over-inflated Marble Pie that was just mere moments away. For whatever reason they decided to talk for some time about the next new party that is going to happen at Sugarcube Corner. Pinkie was talking about her big party plans about, coincidentally, Marble Pie. As they walked, Maud took her time while she lagged behind quite some distance, taking her sweet time. All the while Pinkie bounced ahead of Limestone, excitedly and rapidly hopping in the inflation's direction from behind her. "Wheeeee! I’m soooooo excited for our super-duper-spectacular party we’re gonna be throwing Marble Pie! I can’t wait to see the look on her face when we- Oof!" said Pinkie, bumping into two large and smooth growing masses, that rumbled violently with the pressure reaching maximum proportions.


Pinkie backed up a bit, alongside her two sisters, looking up at the two massive globes of air that were her sister’s massive flanks, inflated to much larger than any party balloon that she’s encountered, oblivious to the fact that it was locked and loaded with backed up air that rushed into their sibling's body...even unaware or the gurgling sounds her body made. Pinkie snorted out a laughter, giving her rump a firm pat listening to the drum like percussion sound it made. "Whoa! Marbles, is that you?! How'd you get so big?! You look like the biggest party balloon I’ve ever—"


"MMMMMMFFFF!!!!" Marble groaned out in a feeble attempt in warning her sisters, though felt she was far too late. Feeling the pressure become too much for her, trying as hard as she can to hold it in she clenched her flanks together hard enough to for sweat to accumulate, feeling the air as it begun to leak through her flanks, creating a small squeaking noise of horror. Pinkie, Limestone, and Maud were all right behind her massive flanks unaware of what will happen next. Pinkie scratched her head and looked at the others obliviously. Marble Pie, on the other hoof, had no choice, as she was giving it her best attempts to not release right in front of them, or worse completely embarrass herself and her sisters beyond belief, even clenching hard enough to make her plot rumble rapidly. Marble, and apparently Maud, both knew it was too late as the pressure became too much, while more air begun to squeak out of her at a quicker pace, making for a pending squealing noise that would lead to an indescribable experience. Before Limestone could muster a complaint about Marble's size being the biggest boulder she'd seen, Maud appeared to the side of her and started, "She’s going to—" Was all Maud could muster out, before…


Marble could hold it back no longer, as with all her might, she finally succumbed to the pressure as her rump rumbled rapidly,shaking profusely as her disproportionately small tail rose instinctively and, without much more warning, Marble Pie squinted her eyes tightly and finally being forced to give up her struggle, as her flanks loosened, her flanks un-clenching and begun to violently release an explosion of toxic gas from her backside,directly into the faces of her sisters, whom were right behind her massive, now farting flanks as the stinky air current continued to blast from her rear right upon her sisters for what seemed like hours, the sound echoing throughout the area for miles, even blowing down trees and bushes, blowing down just about anything in it's path with powerful blasts that erupted from this poor pony's rear, which echoed through the otherwise still air.


PFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFRRRRRRTTTTTTTT!!!!!!!!!!


Marble squeaked and meeped with each second, keeping her eyes tightly sealed as she released her inflated flank farts with such force it made the hair on their heads fly backwards as the hot steamy smelly air expelled from her back end for some time. Marble could only close her eyes, in hopes her air gusts would stop her plot blasts directly into her sister's faces while embarrassed beyond belief, all the while causing her body to begin deflating from the rapid air release all from her big plot seemingly a long,smelly,hot, and tedious process. Just from the force alone, Pinkie had already toppled over onto her back, Limestone struggling to keep her balance and Maud simply took it, standing there without showing the slightest of emotion about the whole ordeal, her mane flowing rapidly with the gusts of hot wind wafting her face, and her body swayed slightly however as if she was just there to take it without giving a flying feather.


After what seemed like hours, which was really only about 45 minutes to 60 minutes of just pure back-blasted farting, Marble’s body seemed to deflate enough to dislodge herself from the depressurized air supply, still farting plot profusely until her body deflated enough, even a little too much as her stretched out body fell limp onto the ground, her skin saggy and wrinkled from the added air exchange, though was otherwise back to normal size. Marble couldn't possibly bare to see her sisters after what just occurred...so she then shuddered and curled up using her saggy skin as a form of blanket, shaking a bit...


The sisters of the previously farting Marble were left dumbfounded by what had just happened, except Maud who didn’t have an opinion on the matters. Limestone finally gathered to her hooves and stormed to Marble. "What in the hay was that?!" Pinkie was next to quickly get to her hooves and blurt out. "Whoa! You really let it rip! Even my party cannon can’t make a blast as big as your flank-cannon did! You should have told us earlier about it!" Pinkie said, as her mane seemed frizzier than ever, if that was possible. The mare looked like she had a pink afro. "Maybe she should rest first." Maud said, pointing to Marble’s tired, wrinkly form. The group all agreed, nodding in unison, looking upon Marble's now passed out saggy wrinkly deflated form.