This is a request from a friend of mine, so don't think I'm odd for Genre-hopping.
Sonic and Shadow ran through the forest, their eyes fixated on the castle looming above them.
"So you're sure he's in there?" Shadow asked Sonic, who was beside him.
"Don't you feel it? That weird, distorted sensation, the one that makes your fur stand on end."
"I didn't pay attention to it." Shadow whispered.
"Why are you whispering?" Sonic asked, quizzically.
"Can't you hear someone laughing?"
A muffled laughter emanated from the castle, which was in plain sight now. Sonic picked up his pace, and skidded to a halt outside the castle, waiting for Shadow to catch up.
"You ready?" Sonic seemed to be mildly aloof.
"You can't zone out on us now, if who you say is in there really is, we're in deep trouble."
They pushed open the heavy steel doors, and entered.
"Welcome, Sonic, Shadow. You look worried." Seelkadoom's ominous figure stepped out from a dark corner.
"No way…" Shadow almost choked.
"What, is it because I'm a combination of your DNA?"
"That and the fact you're even alive." Sonic spoke up for the first time since a while.
"For, in a sense, my parent, you aren't very kind, are you?"
"Depends on which parent I am." Sonic dashed past Seelkadoom, and attempted a kick at the latter's head. Seelkadoom merely raised an arm, blocking the hedgehog, and knocked him backwards.
Shadow narrowed his eyes.
"Chaos Control!" Time slowed down, and Seelkadoom was slow to react as Shadow sped up in front of the other Hedgehog, and attempted a punch.
"Very, very bad…" Seelkadoom muttered.
"What the…" Shadow gasped as Seelkadoom began to pummel Shadow into the ground.
Sonic silently appeared behind Seelkadoom and managed to land an axe kick to the back of Seelkadoom's head.
"Ugh…" The combination of DNA fell to the ground.
"Now…" Shadow climbed to his feet, and stood in front of Seelkadoom's limp body.
"…You go back to where you came from."
"And where might that be?" Seelkadoom groaned.
"Hell." Shadow began to form a Chaos Spear, but Seelkadoom grabbed the Dark Hedgehog's wrist, and stopped it.
"You think I'd go down that easily, after I'm the Superior Hedgehog?"
"Don't sound too sure of yourself!" Sonic shouted, as he Spin Dashed straight for Seelkadoom
Seelkadoom turned around at the last moment and was blasted through a wall by Sonic.
"Too easy…"
Seelkadoom laughed from outside the ominous castle.
"And so you think one measly Spin Dash can kill me? Obviously you think too highly of yourself." Seelkadoom's glare darkened.
It began to rain, but not an ordinary kind of rain.
"This is…" Shadow started.
"Chaos Energy."
Seelkadoom smiled.
Oh dear... Will Sonic and Shadow survive Seelkadoom's oncoming attack, or will he finally actually be the Ultimate Life Form?