Authors note: Hey guys! This is my first fanfic so flame if you want but I won't care. All the characters are owned by Nintendo.

Mario sat on the edge of his bed playing Animal Crossing on his DS.

"There! That's the very last flower," he said putting the last flower in place. "What shall I do now?"

He sat there, thinking about what to do next.

"I'm so bored!" he announced suddenly.

"What's up Big Bro?" Luigi asked poking his head round the door having heard Mario declare his boredom.

Mario sighed. "I'm just really bored," he said.

"Well, we're going to go racing, do you want to join?" Luigi asked.

Mario chucked his DS onto the bed beside him and jumped to his feet. "Do I?!" he exclaimed.

Mario sat in his bright red cart at the starting line. He streached his arms and grinned at his brother who was next to him. Luigi had gone for the green moterbike because he wanted to feel cool.

A lackitu hovered at the start line with a black and white checked flag.

"On your marks," the lackitu said.

The engines remmed and roared.

"Get set,"

Luigi looked at his brother and winked. Mario of course knew that this meant 'Good luck Bro!'

"GO!"

The engines exploded into action. Yoshi roared right to the front, closely followed by Peach. Luigi was in third and Mario was right behind. Mario was determined to beat his brother. It was very close, Mario very nearly overtook him at one point but Luigi used a mushroom and sped away.

After about ten minutes, Mario got a banana peel and threw it at Luigi. It hit him right on the head. Mario cheered and drove up next to him while he was stunned. Luigi hit the side of Mario's cart with his bike. Mario wasn't suprised by this action, I mean, it's Mario Kart; the one rule is: there are no rules. But it was the look that Luigi gave Mario, that suprised him. Luigi stared at him, an evil stare that sent shivers down Mario's spine. Mario backed up, terrifyed.

What Mario didn't know was that inside the banana peel that he had thrown was a strange and special powder and when it hit Luigi, he felt weird and tingly inside, and in only a couple of minutes, he had changed.

Mario decided to give Luigi the benefit of the doubt. Maybe he just got over-competitve or something. He thought After all, it was just a stare.

"Good race eh Luigi?" he said once they got back home after the race. (Peach had won by the way)

"Yes," Luigi said sophisticatedly.

Mario was a little suprised at his sudden poshness.

"Well I'm going to go to bed now, Mario," he said and started to walk out of the room.

"But it's only seven-" Mario started. The door slammed.

"-o'clock." he finished.

Luigi sure is acting strangely. Mario thought.

He decided to play Super Mario Galaxy 2 whilst eating popcorn untill 10:30 then go to bed.

Mario woke up the next day, rubbed his eyes and got up. He went to go and see Luigi. He was intrigued to know whether his brother was still acting strangely. He opened the door to his brother's room, and there he saw Luigi, standing in front of the mirror, wearing a suit. He straightened his emerald-green tie. Mario was stunned, Luigi always wore overalls, just like Mario, so that they matched (I mean they are twins!)

"Luigi? What's with the posh suit?" he asked.

"Oh, good morning Mario," Luigi said taking off his hat and hanging it on a peg. "Well I have to rush, I'm going to the casino."

"Casino? You gamble?" Mario said suprised.

He's deliberately avoiding the question. Mario thought. And going gambling is pretty weird too, he never gambles, he says it's evil. Mario was very mystifyed.

Luigi said goodbye and left.

"I've gotta go tell someone about Luigi's weird behavior," Mario said once Luigi had left. Then he said: "Who am I talking to?"

Mario went to go and visit Princess Peach in her castle.

Standing outside Peach's castle was Toad.

"Hey Mario!" Toad said.

"Hiya Toad, is Peach in?" Mario asked.

"Yep, head on through," Toad replied and Mario walked in.

There he saw Peach talking to one of the Toads.

"...so then I said, 'You kidnap me every week, why do you think I hate you?'" Peach said. Suddenly, she saw Mario.

"Oh, hi Mario!" Peach said.

"Heya Peach, listen, I've got a problem," Mario said.

Peach put her head on one side. "What's that? Is it Bowser again? I swear he-"

"It's not Bowser," Mario interupted. "It's Luigi."

"Luigi?" Peach enquired.

"Yeah, I think something's wrong with him," Mario replied.

"Why do you say that?" Peach asked.

"Well... he's wearing a suit."

Peach blinked. "A suit? That's it?"

"Well he's acting really weirdly too, he talks all posh, and he went gambling just now and he just dosen't seem himself and he glared at me in racing."

Peach was going to say something clichéd about Luigi wanting to be his own person but she was interrupted.

The Toad from outside burst into the room.

"Mario! Peach! Luigi has killed Toadsworth and is heading this way!" he yelled.

Mario looked at him. Then he suddenly snapped: "Toad, what have I told you about pulling pranks! It's not April Fools day!"

"IT'S TRUE!" Toad screamed.

Suddenly, Luigi burst through the door. He had an evil glare in his eye and a blood-stained dagger in his left hand.

"There you are brother," he spat. "I've been searching for you."

Mario's mouth dropped open. "Lu-Luigi?!" he stuttered.

"You may have heard that I killed Toadsworth," he continued. Luigi wiped the dagger clean on his sleeve.

"Peach, run," Mario said realising what danger they were in.

"But what about you?" she asked worridly.

"I'll be fine. Just remember... I love you," Mario replied.

Peach ran out of the room, not wanting to know what would happen next. Peach knew that Mario loved his brother and would never hurt him, so she could imagine that this was going to end badly.

"So, you've saved your little lady friend," Luigi said sounding menacing.

"Luigi, what are you doing? This isn't like you at all, what happened?" Mario asked.

Luigi ignored the question, he had no memory of being good.

"I could kill you right now Mario," Luigi said suddenly.

Peach gasped having heard this and couln't resist peeking through the window to see what was going on.

"No! You wouldn't! I'm your brother!" Mario cried. He was trembling all over.

Luigi began to circle around Mario.

"I could kill you Mario," he said. "I really could."

Mario turned this way and that, feeling like he was being hunted.

Suddenly, Luigi stopped circling around Mario and took a step back.

"I could kill you," he said. "But then my fun would be over all at once. I'll go for now but I will be back for you one day Mario!"

Luigi turned and walked away, laughing menacingly as he went.

Mario was still trembling. Peach came back into the room and put a hand on his shoulder.

"Are you OK?" she asked.

Mario looked at her, they both knew, he was anything but.