Rarity awkwardly straightened her dress, adjusting the straps which would allow the clothing to become several sizes larger if needed. Though not the most beautiful thing she had ever made, what Rarity sacrificed in style she more than made up for in practicality. The entire thing was unfortunately a simple flat black, and hugged Rarity’s curves rather loosely, in order to leave room to expand.
All in all it didn't look terrible, but that was enough to make Rarity fidget in the hand mirror, the girl tugging here and pulling there. Her fingers ran down the smooth fabric again and again until at long last the unicorn sighed, looking down on herself one final time. Her horn was filed perfectly, her dress was as nice as it was going to get and her sandals clad hooves were clean.
Pushing past the final bit of resistance, Rarity reached for the door only to be surprised when it opened before she could even knock.
“About time you decided to come in. How long have you been standing out here?” Spike asked, the dragon leaning against the doorframe, his hands in his hoodie pocket.
Rarity cleared her throat. “I was merely freshening up.”
Spike chuckled. “So like, ten minutes?”
“More like twenty, or so,” Rarity admitted with a sigh.
“Called it!” shouted the familiar voice of Starlight from the other room.
“Yes well. My own awkwardness aside, may I come in?” Rarity inquired.
Spike pulled open the crystal door. “Of course. Did you need something or did you decide to come down just to try and get Twilight to update her wardrobe again?”
“No I’m afraid the reason I’m here is more serious then dear Twilight’s poor taste in fashion,” Rarity replied, glancing left and right. “Where is our resident princess anyway?”
“She's down in her lab,” Spike answered, jerking a thumb over his shoulder. “Down the hall, first stairs on your left. You can't miss it.”
“Just remember to knock!” Starlight shouted.
“Yeah or you might end up turned into some manner of horrible monster like Rainbow Dash was last week,” Spike added.
“Noted,” Rarity muttered, before hastily walking away from the dragon.
Trotting down the crystal hallways, Rarity quickened her pace, the pony glancing nervously through a window, to the sun setting in the distance. “Come on Rarity you still have about an hour or so. You can do this,” she murmured under her breath.
Hastily stepping down the stairs, Rarity found herself in a much darker hallway, at the end of which sat a door that sat slightly ajar. From within Rarity could hear the sound of someone talking as well as the occasional zap of electrical discharge. Walking up to the entrance, Rarity ran a hand down her dress, before knocking twice.
“Twilight darling, are you there?” Rarity called.
“Hmm, oh uh yes. Come in!” Twilight yelled back.
Rarity nervously pulled open the door and stepped inside. “Sorry to bother you, but… oh my. What do we have here?” Rarity inquired, glancing at the large metal objects in the center of Twilight’s lab.
Each was a few feet tall and looked like strange flowers with copper stems and donut shaped silver objects sitting atop them.
“Oh this? This is just a curiosity of mine,” Twilight explained, the alicorn scratching a few notes before facing the unicorn fully. “So, what can I do for you Rarity?”
The fashionista couldn't help but stare at Twilight’s stunning physique, as even partially hidden under the lab coat she struck a striking form. Becoming an alicorn had evidently bolstered her curves, and made the already quite beautiful woman even more fetching. Tearing her gaze from her friend’s body, Rarity placed a hand over her heart, steadying herself.
“Well, there is no easy way to say this but I was hoping to get your help with something,” Rarity began.
“Oh, with what?” Twilight inquired, the woman leaning forward and inadvertently revealing a few inches of her significant cleavage.
Rarity gulped. “You remember the little incident several years ago with that rather vile version of myself, do you not?”
Twilight rubbed her chin thoughtfully. “I do. There aren't any lingering side effects, are there? Luna mentioned that she had nightmares for months after being separated.”
“No nothing like that,” Rarity replied hastily. “It's just that. She never quite left.”
“What do you mean?” Twilight questioned, her brow furrowing.
“Well as you’re aware I haven't partaken in the nightmare night festivities since then and though initially this was out of a distaste for the memories of that rather fateful evening there are other reasons,” Rarity concluded mysteriously.
“She comes back each year doesn't she?” Twilight pressed.
Rarity nodded slowly, silently a little amazed that her friend had managed to guess her problem so quickly. “At first it was just some strange thoughts and odd… urges but last year she very nearly took control. I fear what may happen if she were to get out as it were,” Rarity admitted.
Twilight hummed thoughtfully. “That would indeed be quite unfortunate. Though I already have an idea which may be able to remedy things at least temporarily.”
Rarity breathed a sigh of relief, and wiped a bead of sweat from her forehead. “Oh thank goodness. I worried that I may have put things off for a bit too long given that it is nearly nightmare night already.”
“My preparations will only take a few minutes,” Twilight explained. “If you go to my chambers I will meet you there momentarily.”
Rarity nodded eagerly. “Of course. Thank you Twilight you’re the only one I’d trust with something this important.”
Twilight smiled. “It's my pleasure, Rarity. Anything for a friend.”
Rarity’s heart nearly skipped a beat and the woman hastily turned away from her friend, partially because she wanted to hide her blush.
Grinning excitedly, Rarity happily climbed the steps and navigated some of the many winding halls of friendship castle. Opening the door to Twilight’s room, Rarity strode inside and sat upon the alicorn’s enormous bed, only to notice that something was wrong. Rarity tried to push down her growing erection, but unfortunately the offending appendage seemed to resist her desire to hide it from view.
“Ever since that first night you have been absolutely impossible to control,” Rarity angrily remarked, shoving her dick between her legs and squeezing them tightly, hiding her considerably above average cock.
Hands wringing together, Rarity glanced expectantly at the door, trying to will Twilight into existence. When the alicorn didn't appear after several minutes of less than patient waiting, Rarity looked for a clock only to not find one. Glancing nervously out the window Rarity could see that the moon was slowly reaching its apex, signifying that it was nearly time.
“Come on, come on, hurry up,” Rarity muttered, the girl’s leg bouncing nervously as she peered out the window.
Despite her desire to kill the nervous habit of hers, Rarity found herself unable to do just that, with the pony sitting there awkwardly, her smoldering desire all but forgotten. Smothered by her growing panic, Rarity found herself becoming increasingly worried the longer Twilight was away. Until she began to hear the distinct clack of hooves coming down the hall, finally assuaging her worries.
Briefly elated, Rarity rose to a stand, only to realize she was taller then she had been a moment earlier. Panic now flooding her system, Rarity looked down in horror as her pearl white flesh was slowly turning a murky grey coloration. Even her perfectly coiffed mane was beginning to change, growing longer, wavyer, and shimmering softly in the moonlight.
Conjuring her hand mirror, Rarity gasped in horror as her eyes shifted, her pupils narrowing and becoming the gaze of the woman whom had tormented her every year. Throwing the peice of glass aside, Rarity watched in terror as her nails grew longer, and her flesh became as black as night. With a groan, the woman felt a pressure at the back of her mind, one which grew until she could resist it no longer.
“Finally! I am free!” exclaimed the corrupted unicorn, who stretched her freshly altered body. “At least that fool Rarity finally decided to make something to preserve our dignity.”
The woman looked down at her tight, form fitting dress, and ran a hand across her thigh, with a smirk. “It's a pity. I wear it far better then she ever could,” Nightmarity remarked quietly.
“Ahh, so you are an entirely different being, interesting,” exclaimed the familiar voice of Twilight Sparkle.
The corrupted pony looked to find the alicorn standing in the doorway, a smile on her lips. “Of course we are,” Nightmarity replied dismissively. “Otherwise we would not resist each other with such fervor.”
“I suppose not,” Twilight concluded, closing the door behind her and standing across from the corrupted woman. “Now then, onto negotiations.”
“Negotiations?” Scoffed the dark unicorn. “You say that like you have something to offer me.”
Twilight raised an eyebrow and pointed to the other woman’s crotch.
Nightmarity glanced at her erection before scowling and then quickly schooling her features, the woman wearing a calm mask of control once more. “No matter, I’m sure there are dozens of men and women who will be more than willing to satiate my lust,” Nightmarity exclaimed, running her hands down her sides and emphasizing her curves and hefty H cup tits.
Twilight smiled. “I suppose I will simply have to entice you into remaining here and allowing our negotiations to continue then.”
The corrupted pony didn't even have time to utter a word in edgewise before Twilight dropped her lab coat and kicked it aside. Nightmarity’s cock throbbed and her attention was immediately captivated by the elegant amazon standing before her. Though almost always hidden by loose clothes, or unflattering dresses, Twilight’s physique was nothing less than a perfect hourglass unlike anything Nightmarity had seen.
With breasts large enough to put even the nightmare creature’s to shame, and contained by a lacy black bra which drew in the eye. Her gaze didn't remain on the other woman’s pendulous orbs for long however, as that wasn't the only peice of lingerie Twilight wore. Long stockings hugged the alicorn’s shapely legs, and were attached to a garter belt that hugged the woman’s wide child bearing hips.
Though the midnight black color of the entire outfit initially clashed with the pony’s brighter colored flesh, the longer Nightmarity stared the more she fell in love with it. Not only was it the same shade as the corrupted woman’s own skin, it also perfectly drew the viewer’s eyes to the alicorn’s breasts or crotch. The alicorn even wore lace gloves which stretched up her forearms, completing the outfit perfectly in Nightmarity’s mind.
“Stunning,” Nightmarity declared. “Absolutely stunning. Though I couldn't help but notice you lack any lower undergarments.”
“That would just get in the way. Now then, you must tell me if you...” Twilight smiled, and twirled in place, wings spread. “-like what you see?”
“It's nearly perfect, there is only one thing out of place,” corrected the dark unicorn who lit her horn.
In a flash of magic two holes were cut in the other woman’s bra, allowing Twilight’s nipples to be exposed to the open air.
Twilight chuckled. “Oh wow, that is a nice change. So, have we piqued your curiosity?”
The futa woman smiled. “At first you had my curiosity, but now you have my attention.”
“I’ll get right to it then. I want you to promise not to cause any trouble while you are here, and in return I will have sex with you each and every nightmare night,” Twilight’s smile broadened and the alicorn licked her lips. “How does that sound?”
For a moment the corrupted mare wanted to rebuff the offer, but then an idea occurred to her. “You do know that Rarity has yet to empty these things even a single time since I gave them to her, right?” Nightmarity teased, lifting her dress and hefting her enormous basketball sized balls in emphasis, seed sloshing audibly within the fleshy orbs.
“I am well aware of how backed up Rarity has become,” Twilight replied simply.
Nightmarity grinned. “You underestimate me, good. I will need a loyal sex slave once I figure out how to remain in control and you will serve that role perfectly.”
Twilight smirked. “Well then. How do you want to start?”
The corrupted woman’s confidence flickered for a moment, the alicorn’s sheer conviction causing a bit of doubt to worm its way into her mind. Shaking it off, Nightmarity lit her horn, and tore off her dress in a single harsh tug, bearing her nude form unashamedly. Though not quite as tall, or as possessing of the same perfect physique, the corrupted woman stood proudly before the alicorn.
Her enormous mottled black and white horse cock standing firm atop a pair of balls that would make an elephant envious, the woman herself taking a moment to enjoy what was about to happen. Nightmarity ran a hand down her body, emphasizing her considerable curves before lifting her balls and letting them fall. Seed splashed audibly within her enormous sack, making the woman grin wolfishly at the alicorn standing before her.
“Face down, ass up on the bed right now,” Nightmarity commanded.
Twilight giggled excitedly. “Yes ma’am.”
The corrupted woman’s smile faltered as the alicorn passed her by, finger tips tracing their way across the possessed unicorn’s midsection. The faint touch promised so much more, and Nightmarity couldn't help but feel as though she wasn't as in control as she would like to be. Brushing that thought aside, the woman decided to change that, and strode over to the bed, intent on accomplishing just such a goal.
Only to be temporarily struck by the sight of the alicorn laying on the bed, her enormous breasts pressed against the sheets. Her wide hips were on full display as were her long shapely legs which were spread behind her. Gritting her teeth, Nightmarity walked across the bed before kneeling behind the woman, silently trying to ignore the feeling like she still wasn't in control.
Gripping her long, thick cock in her hand, the futa woman grinned, confident that her inequine length and girth would be enough to accomplish what she wanted. After all, she was bigger than any man, and contained within her an endurance that would put any mortal to shame. Nightmarity was confident that she would break this mare, and claim her first prize, it was only a matter of time.
“What are you waiting for? An invitation?” Twilight teased, giving her hips a shake and flicking her tail back at the other woman.
Nightmarity growled and grabbed the offending clump of hair tight in her grip. “Silence. I will take you when I want to take you and not a moment sooner!”
“Mmm harder,” Twilight moaned.
Grinding her teeth together, the corrupted woman gripped her cock in her magic and aimed it at the alicorn’s dripping hole. “Lets see how you deal with this!” She shouted boldly.
The massive head of nightmarity’s cock slammed into the alicorn’s hole, immediately surprising the corrupted woman when it slid inside with ease. Not only the head entered but a good few inches of the futa woman’s titanic tool followed shortly thereafter. The slick depths of the woman’s accommodating pussy gripped Nightmarity’s tool tightly, pulling her ever deeper.
The act which should have seen control return to her once more only seemed to cement Twilight’s position. One which was made only even more secure when the winged woman pushed back before Nightmarity could thrust forward. Growling angrily, the corrupted woman gripped her lover’s tail tightly before ramming her hips forward, shoving her cock deep into Twilight’s depths.
Like a velvet glove, Twilight’s pussy swallowed it all, squeezing and kneading Nightmarity’s length. Never stretching too wide, or becoming too tight, the woman seemed to have been designed to take Nightmarity’s mammoth cock perfectly. Twilight offered no complaint, and said nothing, merely allowing her partner to take the reins, further annoying the corrupted unicorn.
Growling irritably, Nightmarity threw herself forward, plunging deep into the mare’s cunt and causing her stomach to bulge quite noticeably. If she glanced beneath the woman’s stomach she would have grinned confidently at the indent visible on the woman’s belly. The corrupted woman had no time to do such a thing however, and instead poured everything she had into stuffing the alicorn’s cunt with futa cock.
She was certain that even if things had gone easily so far, that it wouldn't remain that way forever. After all, no one could be as big as her, it simply wasn't possible, and that was one thing Nightmarity was sure of. Yet after only a few seconds she felt her hips connect with the other woman’s, her balls swinging below them.
It was impossible, Twilight had taken every last inch without so much as a grunt or a moment of adjustment. Thinking quickly, Nightmarity pulled back, before slamming back inside the mare, utilizing her magically augmented muscles to her advantage. She repeated this motion over and over, pounding the other woman hard enough to make her own balls slosh audibly.
Yet despite the brutality of her pace, Twilight continued to moan in unabashed lust, seemly completely at ease with the harsh fucking she was receiving. Nightmarity had more tricks then just that however, and the woman lit her horn, conjuring a small buzzing bead which she attached to the other woman’s clitoris. That seemed to earn the appropriate response as Twilight unexpectedly clenched her nether bits, tightening briefly before letting out a deep, contented sigh.
“Oh yeah, that's the stuff,” Twilight muttered between moans.
Conjuring several more, Nightmarity attached them to the other woman’s exposed nipples before making them buzz faster still. Again the alicorn clenched down around Nightmarity’s shaft, and again she quickly adapted, rolling with the punches easily. The corrupted woman quietly began to alter her plan, trusting that this was merely a show of force and that soon the alicorn would tire.
And if that didn't work the unicorn would simply fill her past the point that any mortal man was capable of. That would surely allow Nightmarity to regain the edge she had apparently lost to the secret size queen. Despite the initial set back, the unicorn couldn't help but grin, and flex her muscles, pouring every bit of strength she had into her thrusts.
She was going to ruin the alicorn one way or the other, for her ego demanded nothing short of victory.
Their hips met, sweat poured down their naked forms and breathy moans escaped both women’s mouths as they coupled with a violent intensity. The air was quickly tinged with the scent of arousal, and exertion, though neither party seemed to notice as the minutes flew by. There was only the rhythmic clap of their bodies meeting, and the buzz of Nightmarity’s spells working away at Twilight’s sensitive parts.
Through it all Twilight had yet to orgasm, her body’s rhythm remaining constant even as Nightmarity poured on the speed. The futa woman moved faster, fucked harder, and generally put everything she had into pounding the other woman as ruthlessly as possible. Grinning excitedly, the corrupted unicorn could feel her orgasm beginning to near, confidence surging with each thrust.
A good filling would definitely work, it had to.
Fingers gripped tight the amazonian alicorn’s plush butt cheeks, Nightmarity’s fingernails scratching Twilight’s perfect skin. This elicited another moan from the other woman, making Nightmarity’s confidence surge ever higher. As did her orgasm, which was rapidly approaching, growing stronger each time their bodies met.
“Prepare to be filled and ruined by my perfect seed!” Nightmarity exclaimed haughtily.
“Fuck yeah pump me full,” Twilight moaned back.
Gripping her lover’s ass tighter, Nightmarity threw herself forward for one final time, burying every last inch of throbbing horsecock into the other woman’s pussy. The head of her dick grew, flaring outwards and forcing Twilight’s cervix wide, priming it for the load that was coming. A second later and the first titanic pulse of cum traveled down the unicorn’s cock, the sheer size of which made it visible through Twilight’s flesh.
With a nearly audible splash it exploded into the woman’s womb, filling it to the brim in an instant. The second shot pushed the already stuffed organ to what should be its limits, and the third continued that trend. Yet no matter how much cum Nightmarity pumped into the woman’s womb Twilight always seemed to have room for more.
Over and over the corrupted woman was surprised when she didn't feel seed splash against her crotch after having been forced out by her lover’s overfilled pussy. Even when her balls fell silent, and her cock began to unflare, Twilight remained impassive, and seemingly bored. Glancing down at the woman’s stomach Nightmarity was shocked to find that it had grown to the size of a medicine ball.
The sheer amount of cum inside the woman was astounding, and both parties could hear as it sloshed around inside of the alicorn. Nightmarity had more to give, much, much more, but she had assumed that this fresh immortal would have been laid low by the first emission.
“Done already?” Twilight asked, glancing over her shoulder and revealing a sad expression.
“I am just getting started!” growled the unicorn, who yanked the other woman’s tail with one hand while using the other to shove Twilight back against the bed.
“Well alright then, feel free not to stop next time. I still haven't even finished after all,” Twilight replied simply.
Nightmarity growled. “We will see how cocky you are in a few hours!”
“Mmm I look forward to it,” Twilight purred, the woman spreading herself wide once more.
Her gaze narrowing, Nightmarity ignored the other woman’s word, dismissing them as pointless posturing. Nightmarity was, after all, a being of immense physical and magical prowess, who had the experience of eons on her side. What was this young alicorn to someone like her?
Nothing, she thought.
The corrupted unicorn panted heavily as she continued to fuck the alicorn’s cum bloated form, both hands gripping the woman’s sides in order to not fall off. Her hooves dug into the enormous cum filled belly that had long since crushed Twilight’s bed and raised the pair several feet above the ground. Walking was completely impossible for her lover yet Twilight didn't seem bothered by the fact that none of her limbs could reach the ground and hadn't been able to for several hours.
Instead she seemed incensed by this, and did her best to squeeze down on Nightmarity’s length. She also rocked back against the corrupted woman’s thrusts as best as she could, all while the sound of sloshing cum nearly drowned out their moans. Nightmarity herself had not emerged unscathed and even her enhanced physique was beginning to fail, her muscles burning angrily
Sweat poured down her face, the woman’s hair having long since been tied into a ponytail in order to keep it from hitting her in the eyes. Nightmarity’s magic had been dispelled in order to preserve her power, and even her titanic endurance was reaching its breaking point. Outside the window she could see the moon reaching its apex, signifying that the twenty four hours were nearly up.
An entire day had gone by, and yet here she was, having been unable to make the alicorn orgasm even a single time. So with a single minded determination, Nightmarity poured everything she had into one final round. Her balls had shrunk significantly, and she was nearly out of seed and yet she was determined to keep going regardless.
Switching things up, Nightmarity draped herself across the other woman’s back, using only her hips to thrust into the other woman. No words were said as everything that would have been spoken had long since already been uttered by the pair. Nightamrity merely altered her position enough to get comfortable, and then got right back to work, hardly even slowing her pace.
As what would likely be her final orgasm began to bubble to the surface, Nightmarity idly considered the circumstances she found herself in. Having spent nearly an entire day inside the other woman she was intimately familiar with what her pussy felt like. Yet the act of fucking her had not lost its extrodinary appeal even slightly, nor had the woman loosened up even a little bit after all this time.
She may not have gotten what she wanted, but that didn't mean the corrupted unicorn regretted her actions. After all, there was always next year.
Grunting in exertion, Nightmarity gave it everything she had, pounding the other woman’s pussy with all the fervor she could muster. Not only that but she also leaned forward and nibbled on the other woman’s neck, a tender urge having suddenly welled from deep within her chest. Twilight’s moans grew louder still, and Nightmarity smiled as her own orgasm arrived at the same time she could feel something strange occur.
The alicorn’s well trained muscles were twitching and spasming, as if she were finally orgasming after all this time. Collapsing onto the amazonian’s back, Nightmarity breathed heavily, her cock pulsing as it sent even more cum into Twilight’s bloated womb. For nearly a minute she lay there, struggling to catch her breath, until finally she smiled and spoke for the first time in nearly an hour.
“Well at least you finally came,” Nightmarity remarked mirthlessly.
“It was so worth it though,” Twilight hummed, her body continuing to twitch as she rode out the last of her orgasm. “Stars above thats good.”
“I suppose you aren't about to give up your free will and become my slave huh?” Nightmarity asked.
Twilight shook her head. “I’m afraid not.”
“Worth a shot,” Nightmarity murmured. “I suppose there's always next year.”
“And the year after that,” added Twilight.
The unicorn chuckled briefly before falling limp on Twilight’s back.
For several long seconds nothing happened, until all at once the woman’s coloration reversed, returning to normal once more. Rarity remained just as tall however, and just as well built as her nightmare counterpart had been, with the unicorn herself waking with a gasp a moment later. For a second she merely stared dmbly at her surroundings, slowly piecing together what had happened from context clues.
“Did you… we… oh my,” Rarity whispered, suddenly sounding quite a lot like a certain butter yellow pegasus.
Twilight chuckled, and glanced over her shoulder. “Don't tell me your done. I’m ready for more.”
Rarity’s jaw opened and then closed, the woman struggling to comprehend what happened before erupting with laughter. “You know what they say. Never look a gift horse in the mouth,” Rarity remarked.
With that the unicorn got right back up and right back to work.
Author's Note
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