THE EXPANDING MARSHMALLOW
It was a quiet day in Ponyville; Rarity was just walking back into the Carousel Boutique, having come back from Twilight Sparkle's castle library. Shutting the door behind her she wandered over to her desk, setting the book down; it was one of Twilight's various spell books (She WAS a student of magic, after all). This particular book happened to be on shape-shifting spells. Rarity figured that a new body shape may give her some ideas for some new dress styles; particularly for some of the more “curvaceous” ponies that would come in; also, Rarity wondered what SHE would look like with such a shape.
“Let's see...” Rarity opened the book to “body modification” spells. “Where's the page on body shaping? Hmmm...legs...arms...butt...!!! Aha! Breasts!” Rarity found a breast modification spell on one of the pages. She read it for a bit, to understand it. “Concentrate and read the spell aloud; keep concentration in order for your breasts to grow to the size you want. WARNING: Loss of concentration may cause uncontrollable growth.” Her eyes widened as she imagined herself with breasts bigger than her head and blushed. “Oh my...” Shaking her head to make the thoughts go away, Rarity started to read the spell aloud. “Breastus...Biggus...Swellus...Titticus...” 'What kind of magic words are these?' Rarity thought. Her horn started to glow with magic, before she felt a growing warmth in her chest. “Oh my...I can feel it...it's starting!”
Sure enough, Rarity's breasts began to grow from under her white, button-up blouse. She could feel her shirt starting to tighten.
“Oooooh my...” Rarity purred. “It's starting...” She concentrated, making sure she had the right size in mind. A D-Cup seemed like a reasonable size. But suddenly...
“AH!” Rairty jumped in fright, her concentration breaking. “Wh-What the-- OH NO!”
Sure enough, the magic around Rarity's horn flashed wildly, and the growth rate of Rarity's breasts quickly increased. They went beyond D-Cup...beyond E-Cup! Rarity bit her lip a little as she felt her blouse tighten further. She looked nervously as the buttons puckered and stretched, gaps appearing between them as her “marshmallows” grew to basketball sizes.
POP! POP! POP! POP!
Rarity gasped as her blouse buttons popped off, exposing a pink satin bra with red hearts, stretching along her “marshmallow pair” which quickly inflated to beach ball size. Rarity's face went completely red at her newly grown “funbags” bouncing about. “Oh dear! Th-This is a little more than I had in mind!”
The knocking sounded out again.
“J-Just a minute!” Rarity squeaked, placing an arm over her huge chest and crept towards the door, peering through the peephole. But no one was there. “What?” Rarity questioned out load, and opened the door a little. Again, no one was out there...but there WAS a present on her door step. Rarity looked around to make sure no one was looking, not wanting them to see her ridiculously large breasts, before quickly grabbing the present and disappearing back inside. Rarity looked at the wrapped present and had a look at the tag. “To Rarity, from your secret admirer?” She read aloud. “I wonder who it could be?” Rarity looked back to her chest. “Oooooh, what am I going to do about THESE, though?” She put the parcel down and gave her beach ball bosom a squeeze. “I'd better check the spell book for a counter spell...but first...” She unwrapped her gift, undoing the ribbon, before opening the packaging and the box. Inside was a smaller box, which Rarity took out; it had the smell off freshly baked goods. “Mmmm...whatever's in here, it smells delicious.” When she opened the box, sitting inside, Rarity found 12 dozen cupcakes. They were emanating a freshly baked smell and were covered in chocolate frosting. “Oh! Cupcakes? Did Pinkie send these?” Rarity leaned over, blushing as her breasts squished against the table and had a smell of the cupcakes. “Mmmm...well, perhaps I could do with one now,” she smiled, picking up a cupcake and taking a bite. “Mmm...that chocolate tastes so rich.” Rarity murmured as she continued to eat it up.
Behind Rarity, her butt started to expand outwards as she ate the cupcake, making quiet, stretching sounds as it grew under her skirt, tightening the garment, along with her belt.
Not noticing this yet, Rarity looked again at her breasts, giving them a soft rub and feel. “They've gotten so big...and round...and soft...” She blushed, squeezing them a bit. “They feel quite nice, actually,” she smiled, bouncing them a bit. “And they're bouncy too. Hehehe. EEP! I'm starting to sound like Pinkie Pie!” She reached for another cupcake, picking it up and taking a big bite.
Once again, Rarity's rump began to grow under her skirt, as she ate the 2nd cupcake. Rarity's skirt grew tighter by the second, as her pink satin and red heart panties started to peek out from under it, stretching along Rarity's butt.
“Mmm...the frosting on these cupcakes are so rich and creamy,” Rarity gushed as she picked up the third cupcake and took a bite.
Rarity's skirt struggled to contain her growing butt, until it tore open from the hem up, ripping open and revealing more of Rarity's heart underwear until it reached the belt; both it and the skit popped off loudly.
“OH!” Rarity looked behind, seeing her exposed underwear covering her massive rump. “Wh-What is THIS?” She felt up her big panty butt worriedly. “I've heard of sweets going all the way to your hips or to your rump, but this is ridiculous!” She ran over to the spell book. “There's got to be a way to reverse this spell! Maybe if I activate the spell again and think about shrinking them! Let's see... Breastus...Biggus...Swellus...Titticus...” Rarity's horn flashed with magic, but before she could even think of a breast size, her breasts began to swell again. “EEP!” Blushing madly, Rarity wrapped her arms around her growing bust, as her bra stretched around them. “What next?!” She exclaimed, only for her panty rump to swell like a heart-print satin balloon. “AAAAAAAAH!!!!” She screamed. “I'm turning into a balloon!” Rarity ran towards the doorway. “I need to get help!”
“OH NO!! NOT NOW!” Rarity found herself stuck right in the doorway, her large bust, hips and butt getting her trapped in the doorway. “GAH!” Rarity struggled to get free, but she kept growing. “No! I wanted to be curvier, but not THIS curvy!” Rarity's panty rump stretched and creaked loudly as it took up the entire doorway, making cracks appear in the wall around it.
The doorway bust apart, freeing Rarity. “EEP!” She fell on her front, going face first into her own large breasts, with her rump in the air, wobbling in all it's pink and red heart-print glory. “H-How embarrassing!” Rarity scrambled to get up. Surprisingly, even with her exaggerated growth, she found she could still stand. “I...I can still stand?”
Rarity froze, before slowly looking around her. Numerous colts and stallions were standing there in the street, ogling Rarity's skimpy attire and exaggerated curves. Some eyes were on Rarity's breasts, others were on her gigantic, expanding butt. “Oh no...” Rarity blushed all over, whimpering.
Rarity looked behind her, atop her mammoth posterior, to find Rainbow Dash sitting on it. “Rainbow Dash!?!?”
Rainbow Dash had a huge smirk on her face as she snickered, before it turned to full blown laughter. “BAHAHAHAHAHAHAHAHAHA!!! Have you seen yourself, Rarity? Those huge boobs of yours are one thing, but oh man! This butt's like a mountain!” Rainbow Dash gave Rarity's butt a slap, making it jiggle. “Wow! It's jiggly too!”
“AH!!” Rarity squeaked at the slap. “RAINBOW DASH! Oh, that's IT! Breastus...Biggus...Swellus...Titticus!” Rarity's horn flashed, before she shot a spell at Rainbow Dash.
“OOF!” Rainbow Dash was hit by the spell, which dazed her a bit. “What was...that!?” She suddenly looked down, and noticed HER breasts were starting to swell like balloons. “YIKES! What the heck!?” Rainbow Dash hugged her growing mounds to try and keep them in, only for them to push her arms away, before tearing a hole RIGHT through her shirt, showing a navy blue bra with rainbow prints. Rainbow Dash's breasts grew to the size of Rarity's breasts, but did NOT stop there as they went DOULBE the size. “GAH! What the hell Rarity!?” Rainbow Dash barked, trying to fly up into the air, only for her massive mounds to weigh her down. “ACK! My back!” Rainbow Dash grunted, as she tried to fly, only to fall down, face first into her boobs. “MMPH!”
“Hmph!” Rarity continued on, heading towards Twilight's castle. “Twilight'll know what to do...I hope.” She looked behind. “Oh no...my flank's getting bigger!” She noted that her flank was a lot bigger than even her whole body now. “...why in Celestia's name did I choose today to wearing heart-prints!?” She cursed herself.
Lyra and Bon Bon were just walking by, when they suddenly caught sight of “Rari-booty.”
“Whoa!” Lyra exclaimed.
“Rarity!?” Bon Bon asked.
“Lyra?! Bon Bon!?” Rarity turned around to see the two.
Rarity's irises srhank as she heard a loud crashing sound and looked behind. “OH MY!” To Rarity's horror, the remains of a house lay around where her enormous (and still growing) butt was, bits of wood and cement atop her panty-clad “wide load.” “My butt's become a wrecking ball...” Rarity squeaked. “I have to find Twilight...and quickly!” She turned in the direction of Twilight's castle.
And Rarity's turn made her giant rump shatter another house. “BLAST IT!” Rarity blushed madly and ran; her butt wobbling all the way. Eventually, Rarity made it to the castle. “TWILIGHT! HELP! I NEED YOU!”
Sure enough, Twilight Sparkle came to the window. “Rarity? What's wrong? I heard you shou-WHOA!!!!” Twilight Sparkle saw a huge white mass in pink and red hearts. “WHAT THE HECK IS THAT!?”
“That...is my flank, Twilight.”
Twilight looked down and saw a half naked and VERY embarrassed Rarity looking up at her helplessly. “Rarity!” She leaped out, flying down with her wings, before landing near Rarity. First thing that caught Twilight's eye, AFTER Rarity's massive rump, were her breasts. “Oh my...Rarity, I was about to ask if something went wrong with that breast spell...but judging from your rump, I'd say your breasts are the least of your problems.
“You have NO idea...” Rarity said. “First, I was attempting that spell to make my breasts grow. Everything was going well, until there was a sudden knock at the door. I lost my concentration and my breasts grew bigger than I wanted. I opened the door and found nobody there, save for a present box full of cupcakes. I ate three of those cupcakes and FWOOMP! My butt began growing! I tried to shrink myself down, only for my breasts to get even bigger and my flank even bigger than that! Worst of all, LOOK!” She pointed to her panty rump which was making loud stretching and groaning sounds as it swelled. “It's still growing!”
Twilight gawked at the sight of Rarity's mountainous booty. “Yikes...I can see. Thank goodness you've got some durable underwear.” Then a thought hit her. “Cupcakes you say? ...Let's have a look at them.”
“They're back at the Carrousel Boutique,” Rarity said. “Follow me...and quickly. A lot of the stallions are looking at me with some rather lustful looks.” She waddled on back home.
“R-Right behind you,” Twilight stuttered, mesmerized by the sight of Rarity's butt as she followed. On the way, she noticed the insanely top heavy Rainbow Dash, but she'd deal with that later.
By the time they reached the boutique, they were greeted by some HOUSE and pink...covered in yellow fabric...and balloon prints.
“PINKIE!?” Rarity and Twilight both exclaimed.
The large mass turned, to reveal Pinkie Pie, with a house sized rump, showing off her balloon panties. “Oh, hi everypony!” Pinkie said. “I found some yummy cupcakes in your boutique Rarity and couldn't help myself. But BOY did they make my booty grow all big!”
“I...can see that...” Rarity blushed at the sight of “Booty-Pie.”
“Well, that tells me one thing,” Twilight said. “Pinkie's not the one that sent you the cupcakes.”
“And take a look across Ponyville!” Pinkie pointed.
Rarity and Twilight looked, and their jaws nearly broke through the pavement. All across town, they saw various colored pony butts, growing as big and wide as Rarity and Pinkie's and clad in many styles of panties; heart prints, polka dots, stripes, butterfly prints, fruit prints, and more.
“BAHAHAHAHAHAHAHAHA! Bottoms up, I say!”
Rarity and Twilight heard a masculine voice laugh and looked to the roof of the boutique. Sure enough, there sat Discord, laughing his fool head off, as well as taking a few pictures.
“My, my, my...the mares around here have certainly been screwing up their diets,” Discord chuckled. “All those cupcakes have been going to their butts. I must say, though, they're certainly sporting some sexy underwear.”
“DISCORD!” Twilight shouted. “Is this YOUR doing!?”
“Hmhmhm...you caught me,” Discord smirked, and jumped down. “But the mares should consider themselves lucky. They've got every male in Ponyville fussing over them. They just can't keep their hands off of “DAT BOOTY!”” Sunglasses and a backwards baseball cap appeared on Discord's face.
“Hehe...nope!” Pinkie Pie wiggled her house sized rump.
“Shake those 'thangs, girls!” Discord joked, mimicking a rapper. “Booty, booty, booty! Whoop, whoop, whoop! Booty, booty, booty! Whoop, whoop, WHOA!!” He suddenly yelled out, before a huge white and pink and red heart clad mass came down upon him; Rarity had sat on him! “OOF!”
“HMPH!” Rarity crossed her arms as she sat on Discord. “I'D say, you've hit rock BOTTOM, Discord.”
A little time had passed since the “Cupcake Incident.” Surprisingly, most of the mares were quite happy and WANTED huge butts (The other Element of Harmony bearers included). A huge majority of the Mares in Ponyville relished in flaunting their new figures for every stallion in sight, much to the stallions' delights. Discord, despite being crazy and chaotic, DID have some sense to shrink down the growing mare butts a little, down to at least house-size.
Rarity, especially, liked having a huge butt to show off, coupled with her massive breasts. She literally had stallions throwing themselves at her feet, which she was quite flattered by. Spike, especially, was all over Rarity, often relaxing atop Rarity's house of a rump; Rarity actually thought it was adorable.
At Twilight's castle, Twilight Sparkle was relaxing outside, feeling the warmth of the sun against her own gigantic rump, as it showed off some red and white polka dot panties. “Ahhhh...nothing like the feeling of warm sunlight on the royal caboose,” she giggled.
“Excuse me...Twilight Sparkle?”
Twilight looked up from her sun nap, and saw an equally large rumped Princess Luna, wearing nothing but a t-shirt and black panties against her flank. “Princess Luna? What's going on?”
“There's...a little bit of a mishap in Canterlot, regarding this “big rump” epidemic.” Princess Luna blushed. “You see...Discord played a bit of a prank on my sister, and well...let's just say her own growth went above and beyond.” She pointed in the direction of Canterlot.
Twilight looked over in the direction Luna was pointing to, and her eyes grew immensely wide. “OH MY GOODNESS!!! IS THAT WHAT I THINK IT IS!?”
From out near Castle Canterlot...there was the site of something enormous and round; something the size of the moon. Whatever it was, it was bright yellow, looked silk, was covered in prints of the sun, and some white could be seen, along with the mark of the sun.
“Yes, it is,” Princess Luna said sheepishly. “THAT is the moon-sized rump of Princess Celestia.”