Killua Look:
(Has the clothes of Mario, just no mustache, and clothes are white and blue.)

Story starting..

Bowser Jr walked down the halls of a random warehouse. He'd heard about his father and another man smuggling items, such as shells, coins, gold, and weapons to the Kingdom. He was sick and tired of watching as his father was making money.
"Where are the goods? Pa and Fatty are planning the goods, and I'm sick and tired of my toys.."

Bowser Jr. continued to walk, before a man stopped him. It confused him. It was a Koopa..with white and blue plumber clothing. He shrugged it off.

"Make yourself useful, and help me bring one of these weapons to the Kingdom. " He said, still walking.

The Koopa suddenly dashed towards Jr, throwing him into a wall. Jr groaned in pain. Jr growled, preparing for combat. "Lets fight, Mario!!"
He got into one of his cart-things. (IDK what to call it XDD)

It had boxing gloves. The Koopa ate a fire flower. His clothes changed to red and white.

Quench your thirst for battle! GO for it-
Killua was interrupted, being kicked into a wall by a new Challenger. The clone looked different.

Bowser immediately ran out the warehouse, landing in another area which was a futuristic bridge. Killua saw this and dashed towards Jr, throwing fireballs at him. Jr avoided them, but Killua was right behind him

"Huh? How?!" Jr thought. His cart threw barrages of punches while Killua was in mid air. A large red fist slammed Killua down. Jr's cart kept slamming it fists down onto Killua, but he suddenly jumped in the air.
Bowser Jr tried grabbing him, but Killua threw the cart into a wall, dashing. The cart threw Killua into the wall, knocking him out of the Fire form.

Jr tried throwing punches, but SOMEHOW Killua jumped over him.

He attacked his cart mercilessly, eventually tearing it in half. Killua slammed Jr outside the wall, uppercutted him into the ground, doing twists and 360's as he kicked, and head-butted Jr. Jr was sent flying, but Killua appeared infront of him.

"TASTE MY WRATH." He slammed his knee into Jr's gut.

KO.

Jr tried escaping, but Killua slammed his fist into his chin.

K-
Killua drove his fist into Jr's face, causing a small explosion.

Killua kneed Jr in the face five times, causing a small explosion again. Jr was sent flying, and bounced off a wall. He suddenly was grabbed by Bowser, his father. The angry father turned towards Killua, who's eyes widened.

To be continued..