"Mommy Fwuddewshy!" (Pinkie Pie Becomes a Foal)
Fluttershy woke up to a squeak.
She flew downstairs.
"Is every creature okay?" Fluttershy asked. All of the animals chittered and chattered agreement, that they were okay.
"Okay... Because I woke up to a squeak," Fluttershy said, "and it could only have been one of you."
She flew back upstairs, hearing a familiar voice.
"Mommy Fwuddewshy!"
She looked around. "Pinkie Pie?"
"Down hewe!"
She looked down, gasping at what she saw.
A small, pink foal with a darker pink, bouncy mane and tail.
"Fwuddewshy? Awe you okie?" Pinkie Pie asked.
"H - How are you a foal?" Fluttershy asked.
"I don't kno! I just woke up wike dis!" Pinkie Pie exclaimed. "I'm hungwy! Do you haff any foaw food fwom foalsittin da twins?"
Fluttershy flew to the fridge, opening it. "Hm... Oh, right!"
She ran to the cabinet where she put the tea bags, finding a cup of applesauce. "Perfect!"
She flew upstairs with it and a spoon.
"Thankies!" Pinkie Pie exclaimed, grabbing at the spoon.
"Maybe I should feed you, just in case you're messy." Fluttershy said. Pinkie nodded, as Fluttershy scooped a spoonful of applesauce into Pinkie's mouth.
"It tastes yummiew then any abbosauce I've evew had befowe!" Pinkie exclaimed. "But do you haff any toys for foaws? Cause I'm bowed!"
Fluttershy sighed. "Maybe we should go to Twilight's castle and ask her about this."
"Okie dokie wokie!" Pinkie exclaimed, hopping to Fluttershy. She yawned and said, "Mommy, can we go now? I'm tiwed!"
"I'm not your mother Pinkie. You've been calling me Fluttershy almost this whole time." Fluttershy said.
"I didn't caww you Mommy." Pinkie said. "But I am tiwed! Can we pwease go now? Pwetty pwease wiff chewwies on top!"
"Why is Pinkie Pie a filly?" Rarity asked.
"Well whatever the reason is," Rainbow Dash said, "Twilight isn't okay."
"I don't even kno why I'm a foaw! I just woke up wike dis!" Pinkie Pie exclaimed.
"Well you are absolutely adorable Pinkie!" Rarity said. "Hm... What color would you like for a dress?"
"I don't kno! Oh, duh! Pink! I wuv pink more then I wuv Fwuddewshy! Which's a bunchie!" Pinkie Pie exclaimed.
"Twilight. Twilight. TWILIGHT SPARKLE!" Rainbow Dash yelled.
"Wah!" Twilight exclaimed. "Sorry Dash! I just don't know how this could've happened!"
"Weww I don't mind bein a foaw! I get to spend more time wiff Fwuddewshy!" Pinkie Pie exclaimed. "And I can pway wiff da Cake Twins! They can actuwwy say mowe then my name now! They can say each other's names and awmost can make com-pwe-hen-sive sentences!"
"You had to sound that out?" Rainbow asked. "Honestly?"
"I wouldn't wie! I might be pawt of da Abbo famiwy, wemembew?" Pinkie asked. "And awso Fwudders, how wiww ponies weact to me bein a foaw?"
"Well we could just say that a spell went wrong or something." Fluttershy said. "Or just hope they don't ask? Because hopefully... they won't..."
"Well Pinkie Pie, I don't know any spells that can age a pony up - without using special artifacts, that is." Twilight said. "Fluttershy, would you be willing to take care of her until I find a spell? We can help, of course."
"Fwuddewshy?" Pinkie Pie squeaked. "Pwetty pwease? Wiff chewwies on top? Pwease be my mommy? You'd bwe a gweat one, I kno it!"
"Okay. I'll do it." Fluttershy said. Pinkie Pie jumped into her hooves.
"Yay! Fwuddewshy is da best Mommy!" Pinkie Pie exclaimed. "Mommy, can we pwease go home?"
"Please just call me Fluttershy. Er... Fwuddewshy." Fluttershy said.
"Okie dokie lokie Fwuddews! I was just jokin doe! Sowwy if you thought I was bein sewious! I wuv you!" Pinkie Pie exclaimed.
"I love you too," Fluttershy smiled, "Pinkie Pie."
"Dash, Rarity, Applejack, help me find a spell. Fluttershy, maybe go to Sugarcube Corner. The Cakes can hopefully spare some supplies."
Fluttershy placed Pinkie with the Cake Twins. "Pound, Pumpkin, Pinkie Pie's a foal for now - have fun!"
"Pinkie Pie? How awe you a foaw?" Pumpkin asked.
"I don't kno. I just woke up wike dis!" Pinkie Pie exclaimed. "Can we pway?"
"Suwe!" Pumpkin exclaimed. She hovered herself, Pound and Pinkie down.
"Why hasn't Pound said anythin?" Pinkie whispered into Pumpkin's ear.
"He's shy." Pumpkin whispered. Pound walked back with some toys.
"Hewe!" he exclaimed. There was Pumpkin's butterfly toy, a cupcake plushie, and a plushie of Pinkie.
"Thewe's pwushes of me?" Pinkie asked. "Weww I guess me and my fwiends awe Equestwian famous!"
After playing with the toys for a bit, Fluttershy came back with some supplies. "Pinkie, do you like some of the toys?"
"I dwo! Thewe's a plushie of me! An one of a cupcake! Can we get pwushies pwetty pwease?" Pinkie asked.
"Sure!" Fluttershy exclaimed, hovering the foal onto her back.
"That'll be 20 bits." the shopkeeper said.
Fluttershy got some bits out of her saddlebag. "Why does that foal look so much like Pinkie Pie?"
"Um..." Fluttershy didn't know what to say.
"Cause I am Pinkie Pie! I wandomwy woke up like dis dis mownin!" Pinkie Pie exclaimed, snuggling the plushie of her. "Fwuddewshy, can we go home now?"
"We're finished shopping Pinkie! Do you like the plushies we got?" Fluttershy asked.
"I do!" Pinkie exclaimed. "And the foaw food wiww taste dewicous!"
The foal food was cotton candy flavored, but was also healthy. They got two plushies - the same cupcake plushie that the Cake Twins had, and a plushie of her. And they also got a crib and a mobile.
"Thankies!" Pinkie Pie exclaimed to the shopkeeper, as Fluttershy put her on her back and walked home with all their items.
Pinkie Pie yawned as they entered the cottage. "Couwd you twy to set up my cwib soon? I'm tiwed and want to go to bwed... Yawn!"
"Okay Pinkie." Fluttershy said. She put the food in the fridge, and sat Pinkie Pie on her bed. "Okay... Let's see if I can figure out how to set up the crib."
An hour later, the crib was set up.
"Done!" Fluttershy exclaimed. She turned and saw Pinkie Pie asleep, snuggled up with her plushie.
"Oh Pinkie." she smiled, placing her friend in the crib, with both the plushies and a blanket.
"Goodnight my little Pinkie."
Author's Note
If somepony can suggest a better way to do foal speak please tell me how 
My name is Pinkie Pie (hewwo!)
An I am hewe to say (how you doin?)
We're gonna make you smile,
and we
Wiww bwighten up youw da-aaa-aaay!
It doesn't mattew now (what's up?)
If you awe sad ow bwu (howdy!)
Cause cheewin up my fwiends, is just, what we awe hewe to do!
Okay foal Pinkie Pie doing that is just 
too cute.
