Slendermon

Ash was walking through Viridian forest. He had taken a break from his adventures and wanted to relive the earlier points of his adventure, having no Pokémon with him besides Pikachu. He had a pleasant walk, encuntering no Pokémon for some odd reason. He then saw something interesting: an opening that he never found before! "Pikachu, a secret area! Let's see if anything is in there." "Pika-pika!" Pikachu said while nodding. They walked through the two trees forming the opening, and saw no more little flowers, no more bushes or trees and even heard no Pidgey chirping.

"Umm... Why is this so creepy?" Ash said. It suddenly began to rain, but Ash and Pikachu luckily found a little cave. They went in there, thankful for the shelter. When they went out after the rain, however, they saw a man standing there. It was Professor Oak! Ash came closer and asked what he was doing there. "I have a new method for powering up Pikachu, if you don't mind." Ash wanted to see this and gave Pikachu to Professor Oak. But then, Oak was surrounded by darkness...

He transformed into a creature that was also human-like, and had a tie, two monstrous hands and six tentacles. The worst part: He didn't have a face... He totally ate Pikachu, spilling blood over the grass, which suddenly grew red flowers. Ash ran away, confused and saddened, but the flowers somehow stretched out to tie him down. The monster said: "You wanted to be the very best, HA! You and your Pikachu are pathetic beings, that don't belong in this world. Bye-bye!" The last thing Ash saw was a monstrous mouth reaching for his face...