My Beautiful Dark Twisted Fantasy

Fluttershy was so terribly confused! Twilight had put on weight, and decided to go to the bathroom on the floor… Lightning Dust was so big she couldn't fly if she wanted… Applejack had sent her to get some help bucking the last apples of the season, she hadn't expected this…

*braaaap!*

The blast of warm air caused Fluttershy to fall back on her haunches. It wasn't a very strong blast, or even particularly smelly, but there was something about it… Fluttershy sniffed deeply, not realizing what she was doing. She didn't know that the same magic that affected her two friends was contained in every expulsion

Her whole body started to ache, like that time she and the girls helped Applejack buck apples. 'Oh, that was a lot of exercise,' she thought as her belly began to quiver. Lightning Dust's powerful burp not only increased a pony's weight, but, like herself, caused mind and body to become intertwined, if only for a moment. Like with Twilight, Lightning's memories of flight and athleticism invaded Fluttershy's head. Fat piled onto her frame, yes, but muscle built up over years of hard work layered on top, causing her body to seem soft, yet firm. She gained an extra foot of height, making her the tallest of her friends, and deep inside, her metabolism speed up enough to maintain her strong-fat form.

Her mind changed as well. Shyness was incompatible with loud, boisterous Lightning Dust, and her mind settled on proud confidence in herself. After all, she was a pegasus who could buck like an earth pony! Now she remembered, she needed to help Applejack buck apples! She bid adieu to her friends and hurried out, hoping there would be snacks waiting at Sweet Apple Acres.

Fluttershy walked off, mares and stallions alike staring at her firm, round plot. The confident mare let off a loud fart in their direction, ignoring the moans and shrieks as the ponies behind her began to change. She was strong…

Flutterstrong!