Author's Note

I got this idea from talking to a bunch of MLP WG fans on SquishyLuna's stream a few days ago. Thank you to PhealGud, and to everyone else who was on the stream (if you let me know you were chatting with us, I'll give credit where its due). So I hope everyone enjoys!

I might make this a multi-chapter. I don't know yet. Please let me know what you think.

The Stretch Mark Crusaders Begin

Sweetie Belle left the Carousel Boutique, squinting up at the sunlight she hadn't seen in almost a week. She'd been stuck inside with Rarity, as she'd been helping Rarity with a massive order of dresses that had come in just before the start of the summer. In that time, Sweetie had been unable to do much beyond sit and wait for whenever Rarity needed her. Then, it had been trying to stay as still as possible while she held whatever it was that Rarity needed.

All the while, Rarity had been too stressed out and had been working too hard to cook. Rarity had ordered the pair of them vast quantities of take-out so they didn't have to worry about losing time to cooking. This morning, Rarity had taken one look at Sweetie, and suggested she should go outside for some 'exercise', though Sweetie couldn't guess why.

Walking outside in the fresh air, Sweetie slowly made her way to the clubhouse that she and her two other friends, Apple Bloom and Scootaloo, frequented. On the walk over, across Ponyville and out to Sweet Apple Acres, Sweetie noticed something odd about her body.

Usually, the walk would have been nothing, but halfway there, and Sweetie's legs burned with exhaustion. She panted for breath, and sweat was beading on her forehead. Sweetie took a deep breath, and forced herself to go on. I can get a glass of water when I get there.

By the time Sweetie made it into the clubhouse, she was utterly exhausted. The second she crossed the threshold, her legs gave out from under her, sending Sweetie to the ground.

“Are you alright?-” Scootaloo gave out an excited gasp, “Oh! Is that your Cutie Mark?!”

Sweetie's brows furrowed in confusion. She lifted her head, and twisted around to look at her flank. It was blank as usual, wasn't it?-

Sweetie let out an excited gasp. It wasn't a Cutie Mark, at least it didn't look like one, but there were several indents in her skin that looked like lines, “That can't be a Cutie Mark!”

“What are they then?” Scootaloo asked, bending down to examine the lines closer.

“Ah think they're stretch marks!” Apple Bloom pronounced.

Sweetie Belle jumped at her friend's sudden appearance, “What are those?”

“My Mom had them on her tummy. She always said they happened after she had Big Mac, Applejack, and ah,” Apple Bloom explained, “She said they happened when parts of you got bigger. Applejack has some, too.”

Sweetie sat up, her face burning hot, “It's not like my butt got big-”

“Uh. It kind of did,” to prove her point, Scootaloo poked at Sweetie's flank with her hoof. Sweetie watched in equal parts horror and equal parts fascination as her flesh jiggled a bit.

“Since they appeared on your flank,” Apple Bloom began thoughtfully, “Maybe it's a hint about your Cutie Mark!”

“Is there a weight gain Cutie Mark?” Scootaloo asked, her face scrunching up in thought.

“Ah don't know, but it's worth a shot!” Apple Bloom exclaimed, “We've got to try!”

“I don't know,” Sweetie Belle eased herself into a sitting position, suddenly hyper-aware of her slightly larger body, “It's not like I've gotten my Cutie Mark yet.”

“You're not big enough yet!” Scootaloo stated simply, “How do we go about getting bigger? How's you do it, Sweetie?”

“Well, I didn't do much physically,” Sweetie answered slowly, “and I got bored so I ate a lot of the junk food Rarity bought, and I ate a lot of the take-out she ordered-”

“So, we have to eat at Sugarcube Corner a lot and not do much? That sounds super simple!” Apple Bloom beamed, “Ah think this is it, girls. We just have to stick it out long enough!”

Sweetie Belle began to get excited at the prospect. Who doesn't want to do nothing and eat all day? Besides, if this isn't our special talent, we can just lose the weight! Feeling secure in the knowledge that her closest friends would gain weight with her, Sweetie forgot about the sly, almost disapproving, looks Rarity had been giving her before she left.

(LINE BREAK)

Several Weeks Later…

Sweetie craned her neck up so she could peer over the bulge of flesh her belly had become in the weeks since the Cutie Mark Crusaders had decided to try getting a weight gain cutie mark. Sweetie had taken great strides in trying to keep herself the heaviest of the three, and she couldn't help but enjoy the thrills of watching her body, and the bodies of her friends, expand as a result of their overeating and laziness.

Scootaloo was propped up against the podium, rubbing her stomach with her hoof, a blissful smile and vacant eyes telling Sweetie that the pegasus was in a food coma. Looking around allowed Sweetie to find Apple Bloom in a similar situation, laying on her side, and wrapping her front legs around her bloated stomach.

Sweetie set her head back onto the wooden floor, watching as he belly jiggled with each breath. Moving a little made Sweetie winced as her hooves, and her new fat, pressed against the take-out containers, candy wrappers, and other remnants of their binge.

“We're gonna have to clean this up before Applejack sees the mess,” Apple Bloom mumbled, absentmindedly stroking her soft belly.

Scootaloo let out a groan, “Do we have to right now?”

“Should do it soon,” Sweetie grunted, rolling to her side and ignoring the crinkles that occurred when she trapped wrappers under her, “I have to get back home soon.”

“Yeah, I suppose so,” with a grunt of effort, a lot of wing-flapping, and some sweat, Scootaloo was up on her hooves. Out of the trio, Scootaloo had most of her weight centered on her belly. Her stomach hung down nearly to her knees, making her once energetic walk a slow waddle.

Apple Bloom groaned, and rolled onto her stomach before getting to her feet. Her newly acquired adipose hadn't settled into one specific area, instead coating her whole body in a thick layer of fat, making her jiggle no matter what she did.

Sweetie sighed, getting up as well, making sure to brush the wrappers from her coat where they had stuck to her side. She used her magic, falteringly, to help the others gather up the trash, then sat back down once the chore was taken care of.

Sweetie, as the heaviest of the CMC, had gained quite a bit more weight than her friends. Her belly hung low, just shy of Scootaloo's, while her plot had doubled in size. They jiggled, wiggled, were covered in stretch marks, and had developed a slight crease where they met her hind legs. If Sweetie looked down, a double chin was also prominent.

While the CMC were happy with their new sizes, the reactions of those around them were not quite so...supportive. Rarity had been harping on Sweetie since the day she had first noticed her gain. Applejack was in a similar position, while Cheerilee had sat the CMC down to talk about the dangers of what they were doing.

Sweetie Belle, Scootaloo, and Apple Bloom didn't care. They were set on their new lifestyles, and they had done everything within their power to speed up their gains, to spite those who worked against them. It had worked. They were the heaviest fillies in Ponyville, and they were proud, even if strutting their new figures around Ponyville was getting harder and harder to do every day.

Sweetie smiled, staring down at her globular belly, poking it so she could watch it jiggle. I wonder how much bigger we have to get before getting our Cutie Marks?