Disclaimer: Pokémon is the property of Game Freak, Satoshi Tajiri, and Nintendo. Original story, The Very Hungry Caterpillar, by Eric Carle.
THE VERY HUNGRY CATERPIE
In the light of the moon in the Viridian Forest, a little egg lay under a leaf.
On Sunday morning the warm sun came up and – pop! – out of the egg came a tiny and very hungry Caterpie.
He started to look for some food.
On Monday he ate through one Cheri Berry, but he was still hungry.
On Tuesday he ate through two Chesto Berries, but he was still hungry.
On Wednesday he ate through three Oran Berries, but he was still hungry.
On Thursday he ate through four Pecha Berries, but he was still hungry.
On Friday he ate through five Sitrus Berries, but he was still hungry.
On Saturday he ate through one Rawst Berry, one Aspear Berry, one Leppa Berry, one Persim Berry, one Lum Berry, one Figy Berry, one Starf Berry, one Aguav Berry, one Salac Berry, and one Apicot Berry. That night he had a stomachache!
The next day was Sunday again.
The Caterpie ate through one nice green leaf, and after that he felt much better.
Now he wasn't hungry anymore – and he wasn't a little Caterpie anymore.
He was a big, fat Caterpie!
He built a small house, called a coccoon, and evolved into a Metapod.
He stayed as a Metapod for two weeks.
Then he nibbled a hole in his coccoon and pushed his way out.
He became a beautiful Butterfree!
Ash closed the book and looked down at the little black-haired baby boy cradled in between his arms. "Well Zacky, did you like it?" he asked gently. The tiny little baby wiggled a little bit in his Pikachu onesie and yawned.
"Awww, ready for bed? Okay." Ash set the book down and picked up the baby as he stood up. Little baby Zack closed his eyes and leaned his head against his father's chest as he carried him upstairs to the nursery. Ash ever so carefully lowered him into his crib and rested his head down on his little pillow. As he looked down smiling, Richie entered the room. He brought a stuffed Pikachu toy over and set it down in the crib next to Zack. The baby boy pulled it close with his tiny little arms and snuggled it warmly as Ash pulled his yellow blanket over him.
"Nighty-night, Zacky." Ash leaned over the side of the crib and kissed his adopted son on the forehead before leaving the room with Richie, closing the door quietly behind them.
Short fic (my shortest ever), but I felt like I just had to write it on impulse.
For those of you who are questioning the ending, Ash and Richie are married and have adopted a little bundle of joy named Zack.