-1This is my first Mario fic. This is my first sonic fic. This is my first crossover fic. Enjoy!

"What is it?" Luigi asked as he took a step back.

"It looks like a portal of some sort. Maybe we should go back to the castle and have toad inspect it." Mario said as he rubbed his chin. The brothers nodded in unison and ran off.

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"Face it Eggman, you'll never beat me!" Sonic taunted as he punched another monkey robot in the face, knocking it down and out. Eggman laughed.

"Oh yeah Sonic? How about you try this on for size?" Eggman laughed as he pulled out lever.

"This lever controls all the dynamite in the forest. If you attack, I'll pull this trigger and we'll all die!" He said, an evil smile forming on his lips. But out of nowhere, he was hit by a spinning black ball, knocking the lever out of his hands.

"Nice you could make it Shadow!" Sonic cheered as he raced for the lever. With his speed, he had it in his hands instantly. Unfortunately, he got blindsided by a robo monkey slamming its fist against his skull. The lever slid away. Shadow jumped at it.

"I don't think so!" Eggman yelled, firing a gun that released a rope. It wrapped around Shadows legs and pulled him to the ground.

"I'll get it!" Sonic shouted. Eggman did what he did to Shadow to him. Big came into the clearing. So did Amy and Tails. They took one look at the monkey army, and the situation, and jumped into action, fighting the monkeys and Eggman. Except Big. He walked up to the lever, and picked it up.

"Ooooh, Big wonders what this does. Do you want to know Froggie? I do to." Everyone stopped fighting. Amy had her hammer in mid-swing. Tails had on of his tails sticking through the heart of a robo. Sonic and Shadow were in the process of untying themselves. Everyone stared at Big. Then, everyone began shouting.

"No Big don't!" It was too late. Big pushed down the lever, and there was a loud explosion. Everyone found themselves flying through a dark tunnel. They reached the end, and were spit out right in front of a large castle.

"Agents of Bowser spotted!" Came a high pitched squeak. Amy, Sonic, Shadow, and Tails looked around. They were in front of a huge castle. A man wearing green, a man wearing red, and two odd looking turtle things wielding hammers ran out. They didn't look friendly. Shadow stood up.

"Let's rumble!" He leapt at the group. Sonic and the others followed suit. Tails flew up on top of the castle. One of the hammer guys followed. He swung both tails at the thing, but it knocked them away with its hammer. Daisy was clashing her hammer with the other hammer dude's hammer. It was eerily reminiscent of a hammer swordfight. Sonic squared off with the guy in green. He appeared too scared to fight him. But the real battle was Shadow and Mario. They battled high above the clouds, trading fierce blows. Suddenly, Mario's hands began to glow a fiery red, and he unleashed a storm of fireballs.

"I've gotta counter. Chaos, CONTROL!" Shadow said. The blue from the chaos control hit the red from the fireball storm. A giant explosion erupted, and the two fell towards the ground, pieces of the heavens falling with them. Mario did the fireball storm again while falling. Shadow countered with his chaos control. The two connected, but this time the explosion was so big, it went on to hit the castle! The structure crumpled to the ground. Tails struck the hammer guy with his tail, and then used his tails to fly away, while it was killed by the castle's crumpling. Mario landed on his feet in the middle of the wreckage. Shadow did as well. Luigi ran up to his brother for support. Sonic did the same for Shadow. Mario looked around.

"Thank god the entire castle was out to investigate that portal." He said. Luigi nodded.

"But now we have to deal with these goons of Bowser." He said while putting a hand on his brother's shoulder.

"Careful, these guys have powers that I've never seen before." Mario said. Luigi nodded.

"I'll be careful, but we have to get rid of these guys quick, before Bowser sees we're vulnerable. If he does, we're doomed." Luigi said. Then, a deep, scary voice sounded in everyone's heads.

"It's too late for that green 'stache. It's too late for that…"

Whew! That was actually pretty fun to write. Please leave a review! I need to know if you people like it.