There was one night at Hogwarts that changed everything.

It wasn't when three Fifth Years became Animagi for their werewolf friend.

It wasn't when Severus called Lily a mudblood.

Not even when Lily decided to go out with James.

It wasn't even the night when Severus told Dumbledore of the prophecy.

It was the night Fred and George Weasley were admitted to Hogwarts.

It wasn't like the other Sortings at Hogwarts. This night, Fred and George came up with a clever prank.

When Fred was called for Sorting, everything stayed normal for just a few more precious seconds. Then the Sorting Hat starting scolding the ginger boy for being George Weasley.

The Professors (most of whom remembered the Marauders) shook their heads. Most of the students did as well before they started laughing.

But for a certain dark haired Third Year in Slytherin, he felt a mortal's light bulb go off above his head.

And when the professors went to sleep that night, they shivered. Something had changed at Hogwarts. And they wouldn't like it.

==ANB==

Fred and George loved their first month at Hogwarts.

They could do so many more pranks with what they'd been learning. They loved Charms class the best. They'd accidentally made a bear into a spider when they were kids, it would be great to be able to do that again!

It had been on their first proper try of a prank that they got into trouble for. Fred and George had used their wands in the corridor, trying to tie a Slytherin's shoelaces together. Filch caught them, immediately sent them to detention.

After their last class, they went to Filch's office. He went off to follow his old cat. Fred and George didn't care. That meant they were let out of detention!

Or so they thought. Filch just made the Slytherin who they tried to prank in charge of them.

The Slytherin was taller than Fred and George. He had slimy slick black hair, green eyes, and skin so pale it belonged on Professor Snape. He was staring at Fred and George with this kind of thing that made Fred and George feel like

"I'm Fred!"

"And I'm George!"

"I don't care for your pathetic mortal names." The boy waved them off.

"Well we don't care about your name either!" George shouted at him.

You're a slimy snake!" Fred shouted.

"You know, I actually turned into one when I was a boy to scare my brother." Loki smiled fondly. "Those were the days."

Fred and George didn't like him much more after that.

"Will you just let us out?" Fred asked.

"No I won't, Forge." Loki replied. He couldn't remember the mortals name, why would he have? He wasn't his pathetic brother.

"My name is Fred!"

"I don't particularly care about your names. Filch has entrusted me with your punishments. I intend to see it to the end. I'd rather not lose my House points because your pathetic reckless pranks."

"Reckless!" One twin cried out in offense.

"Pathetic!" The other joined in.

"Yes, it was." Loki motioned down to his shoes. "The laces on my shoes are Charmed not to be tricked by tying charm. You could have tried the, oh what was it called, 'jelly legs jinx' but that spell is too intricate for a pair of First Years."

"Oi! We can do intricate spells-"

"-and we didn't know you're shoes were Charmed!"

Loki rolled his eyes. The Twins were going to do this all night, weren't they? He had better things to do. He wanted to get back to his vengeance.

He had made a mistake when falling off the Rainbow Bridge. It had caused him to fall through time. He landed in Scotland, 1986. He couldn't gather enough magic to travel forward in time. He couldn't take the chance of calling for Heimdall. The old Bridge Keeper would know doubt take one look at Loki and know everything that had happened.

He had worked out a plan to survive in the Midgardian's magic realm. It was going to take many years of work. The longer he studied at this Hogwarts, the stronger his magic became. His magic was like a muscle that he had drained, he needed to work slowly to restore it to it's former glory. He had enough to disguise himself as a growing Midgardian, in addition to his magic for class.

With the bits he had left, Loki made sure no one noticed.

Loki could have survived his remaining twenty-two years before catching up with the proper timeline. Those years were a blink to an Asgardian-

-And to a Frost Giant-

-which would give Loki plenty of time to work out vengeance against Odin.

But first, these two.

Oh, the Twins. Loki could see that mischievous spark in them from day one. They'd done some interesting pranks before being caught. Loki's personal favorite was the time they'd turned their straws in Transfiguration into magical darts that followed their victims and poked them at random times. It was far better than he expected of the mortals.

And if Loki was going to be stuck on this path, he might as well make some mischief.

He pulled open one of Filch's drawers. "Well next time, learn about the person before you prank them."

"We're not taking any-"

"-advice from a rubbish Slytherin!"

"Then at least take this from Filch." Loki handed them an aged piece of parchment. "You'll be needing this, if you want to avoid being caught again."

George took it from him. He opened the paper up. "It's blank."

The God of Mischief pulled out his wand (really just a stick he'd found, disguised to hide his magic) to tap the paper. "I solemnly swear I'm up to no good."

The image came to view. It was blurry at the start. The reds and browns took shape. They became corners then corridors then whole floors. Little black footprints came up next, little white banners with names written in surprisingly fancy handwriting above them.

Messrs Moony, Wormtail, Prongs, Padfoot present: The Marauders Map

Fred and George stared at it in wonder.

Oh yeah, Loki was gonna have fun. "It's always honest, and it shows everyone here. To make it go away." He taped the paper again. "Mischief managed."

The map disappeared faster than it appeared. George quickly tucked it inside his robes. "Why're you giving us this?" George asked.

"Yeah..." Fred wondered.

Loki shrugged, trying to look nonchalant. "From one mischief maker to others, you're going to need the help. Now get out of here."

"No detention?" One asked.

"From a Slytherin?"

"What is this?"

"Are you pranking us?"

"Is Filch watching?"

"You're being controlled, aren't you?!"

"Your punishment is that you can't do any pranks until you learn to do them perfectly. It's not a good prank if you get in trouble, but rather the other person does." Loki instructed.

Fred and George accepted that. They didn't want to chance a real detention with Filch. They might have to clean the trophies or Professor Snape's dungeon!

They got out of their seats, running to the door.

"He called you Forge." One twin laughed.

"I know. Gred!" The other laughed, mocking his brother. He ran off, going towards Gryffindor Tower.

If they had looked at the room they were in, they'd see they were standing in front of Loki Laufeyson, because the Map never lies.

Loki waved his hand. His magic melted away from the desk, revealing a sleeping Filch using Mrs Norris as a pillow. The squip janitor and cat were in a deep sleep. They'd stay that way until morning.

==ANB==

AN: Thanks to pokeloon15 for the story idea!

This is supposed to be a oneshot. If you guys like this, maybe I'll add more to it!