Pokedex entry :
"Sneasel scales trees by punching its hooked claws into bark. It seeks out unguarded nests and steals Eggs for food while its parents are away."

The young woman suddenly stopped to cook the Pidgey eggs as she heard something moving nearby. She stood up, looked in the direction of the sound and couldn't believe what she was seeing before her. She heard about this Pokemon but she would have never thought to meet it... it was a legend.. Celebi...
First, she was amazed, but quickly, her joy transformed into fear as the Pokemon didn't seemed happy.. really not happy... and before she could do anything, it shouted its name as a strange green light appeared in its hands.

The light, then, began to surround the young woman, a little lost, stressed, about the situation and what Celebi was doing.
A strange feeling began to grow inside her. It was like a tingling sensation and the forest seemed to become... bigger?
She stared at her hands and opened her eyes in shock. What was happening to her hands? They were loosing their color but.. most importantly.. her fingers were... merging?...
The young woman couldn't think of anything and just continued to stare at them as they strangely became... harder... sharper as well... It was looking like she had some strange kind of claws... and suddenly, her shoes burst open as her feet seemed to have taken the same direction, revealing white and sharp claws.

The forest continued to "became larger" around her and slowly, her clothes began to fall. Was she shrinking? The doubt may be real, but it seemed it was the case as her pants fell on the ground and her panties was slipping on her legs, revealing another strange vision : Fur... she was growing a dark blue shade of fur, slowly growing over all her body.
The girl was scared and couldn't understand what was going on.
Three pink feathers suddenly sprout on her back, attached to her tailbone as her panties finally fell on the ground.
She couldn't see it, but she could feel that something similar was growing on her head, another feather, slowly replacing her left ear while her right ear seemed to be able to hear sounds she never heard before...somehow.
The woman was now covered in fur... she shrank so much... the forest was a giant to her. And yet, it wasn't over...

The young women tried to stop her shirt, her remaining cloth, to feel on the ground like the others, but with her new claws, she only was able to tear it apart, revealing how the fur was now thick all over her. She could also feel something pushing on her chest and head... and soon enough, strange yellow gems appeared. It wasn't jewelries.. it was part of her.
She was looking lost between her lost clothes around her, now, clearly too large for her. Then, the last changes happened.
Her nose and mouth were feeling like they were pulled out of her face as they slowly formed a muzzle. Her teeth becoming sharper and her tongue filling the new available space. Soon, her face wasn't human anymore. In fact... she wasn't human anymore... and like a proof of this statement, her pupils slowly became more "feline" and turned into a deep red color.
She wasn't a women anymore. She was now... a Pokémon...a Sneasel.

The new Pokémon looked at Celebi, lost, the fear in her eyes. Celebi only answered with a smile and a giggle. Its job was done here and the legendary Pokemon vanished in the forest.
The Sneasel looked up, at the sky as a Pidgey was flying by. She couldn't tell why but she had the feeling this Pidgey was linked to her fate.
She approached the nest, nearby the fire, and took the last egg before disappearing with it between the trees.

Sneasel TF for an Anonymous commissioner.
It seems like stealing Pidgey eggs for dinner wasn't the best idea as their parents called Celebi to "fix" a little the situation.
At least, now, she would have a good reason to steal eggs from nests.