Pinkie the Cannon
Pinkie sighed sadly as she entered Princess Twilight's castle. Her party cannon wasn't working properly, and she wanted to use it to surprise the alicorn. Twilight came up to her, and asked her what was the matter, she wasn't her normally bouncy self.
Pinkie explained the situation, including that she had several other ponies she needed to use her cannon for, but the cannon repair shop in Canterlot was several days away by train, and she wouldn't be able to get the cannon repaired in time for what she needed it for.
Princess Twilight's face lit up with a smile, a bit devious. "I have just the solution for that, Pinkie!" She beckoned for the pink earth pony to follow her.
Pinkie Pie hopped excitedly behind her, into a room filled with... oh, books of course, Princess Twilight's favorite thing!
Twilight positioned Pinkie in the middle of the room in an open area and instructed her to stay there, then taking a book from a high end shelf with her magic, to begin flipping through it quite happily.
The pink pony hopped in place, she could never stay still for long. "So what are you looking for Twilight, is it a spell to fix my cannon?!"
"Not quite!" Twilight said, smiling. Pinkie looked confused for a moment. "But you said that you have a solution for my cannon being broken!"
"Oh Pinkie, I've been wanting to try this transfiguration spell for a while! This won't FIX your party cannon, it will TURN YOU INTO ONE! NOW HOLD STILL!" she said, as a bolt of her magic shot out of her horn right at her earth pony friend.
Pinkie didn't move, for once she was surprised herself.
In a flash of the alicorn's magic, it was done. Twilight circled her, quite pleased with the results. Pinkie whimpered, her face was on the floor, how was she gonna do anything if she couldn't get around and her face was pointed at the ground?!
"Oh, of course, a modification I think is in order!" Twilight said. "Silly me!" With another bolt of magic, Pinkies from hooves appeared on the front of the cannon.
Pinkie Pie reared up excitedly, and began zooming around, now that her back legs were wheels and she had front hooves, NOTHING WAS GONNA STOP HER FROM SURPRISING THE PONIES OF PONYVILLE, AND WHAT A SURPRISE SHE WOULD GIVE THEM ALL!
"Come back when you want to change back Pinkie, I need to test that spell too-" Twilight started to tell her, but it was too late, as her friend had already zoomed out of the Princess' castle and out to bring the joy of her cannony self to every pony she could find!