One sunny day while Ash and everyone where taking a nap, the Pokemon were out playing, doing those types of things they always do on the ridiculous shorts they have at the beginning of the Pokemon Movies. Pikachu was bobbing along, holding and apple and making ridiculously cute anime faces when suddenly... he TRIPPED over something. It was a Book! With a pencil!
Delighted, Pikachu picked up the noteboook and looked at it. "Whoever's Name is written in this book will DIE!" He thought to himself.. of course is was something like; 'Pikapikapika chu chu pika pika chu!' but whatever. Pikachu's eyes narrowed. and he grinned maliciously. No more Togepi stealing the Cuteness Spot. And so he began to write furiously in the notebook. He wrote and he wrote and he wrote.
Suddenly Pikachu's head exploded violently. Ash woke up and ran into the clearing. He was never sure however why there was his pikachu, sans head, lying acorss a blood splattered notebook with the words 'Pika pika pikachu pikachu pika chu chu chu pika pikapi pikachu!' scrawled across it.
And that's why there should never be a pokemon/deathnote fanfic.