The boring stuff: I am not J.K. Rowling. My bank balance confirms this. I own nothing.

One idea per chapter. I am going to do my very best to be original, and I apologize if I accidentally copy something. This will be somewhat AU. Voldemort is alive, but no-one (Cedric included) has died. Any other things you need to know, I'll mention it accordingly.

With that out of the way…

Gred and Forge Must Not, chapter 1.

1. Gred and Forge must not Polyjuice the boys of Gryffindor house into Harry Potter, then argue over which is the real one.

Fred shifted the schoolbag slung over his shoulder. It was heavier than usual today, packed with a copy of Moste Potente Potions, the necessary ingredients for Polyjuice Potion and two shrunken-down cauldrons. While he waited and kept a watch out, George summoned up the Room of Requirement to become a potions lab.

Moments later, the door appeared and the twins slipped inside with furtive glances in either direction. The potions lab that awaited them was perfect, looking very much like Professor Snape's own classroom lab.

The twins prepared the mixture as they needed, each hovering over their own cauldron. At last, they were done and ready to let the potion sit for the month it needed to. In that time they would need to procure a few last ingredients, including the hairs of one Harry Potter.

The next few weeks passed reasonably uneventfully, for Fred and George. One night Fred managed to sneak into Ron's dorm, where he found Harry's hairbrush and stole several hairs and secured them in a small vial.

Finally, the potion was ready. Before dawn, each twin donned dark clothes and cast Disillusionment Charms, sneaking out to their lab to bottle the Polyjuice. Unknown to Harry, they had been persuading some of their dormmates to join in the insanity. Seamus, Neville, Dean, Ron and Lee had all agreed. It hadn't taken much more work before Colin and Dennis Creevey had signed on, and the twins were-of course-also planning to take part.

Each twin had transfigured copies of Harry's glasses and small flasks for the boys to keep a measure of Polyjuice throughout the day. It also hadn't taken much effort for them to alter the sizes of their uniforms to match Harry's.

Not long before the rest of the school was waking up, the twins went and summoned the others to the Room. Here, they distributed the glasses and flasks of Polyjuice, watching in anticipation as their seven housemates got taller or shorter, dark hair and that famous lightning bolt scar. Clinking their flasks together, they drank and felt their own transformations.

After that, it was quick work to change into their uniforms and remind their conspirators to drink the Polyjuice at least once an hour. One by one, the nine Harry Potters exited the Room and headed for breakfast.

The Hall was mostly empty, due to the early hour when Harry Potter came in. Nothing seemed off about it, except that Harry was already present and already halfway through his own breakfast.

A few minutes, the next Harry appeared. Teachers and staff alike filtered in, not noticing the unusual phenomenon at Gryffindor table. Dumbledore seemed to have noticed, maybe. That twinkle was in his eyes, as always.

More Harrys appeared, and still no-one noticed. Each Harry that arrived settled in, taking breakfast and keeping his head down.

Dumbledore stood to make morning announcements, and as he did, Harry looked up. As soon as he had, all nine others looked up as one.

The reaction was instant.

McGonagall spilt her tea; Snape choked and several students looked slightly scared.

Dumbledore braced himself. He wasn't sure he really wanted to do this, wasn't sure it was a good idea at all. Doing so could only lead to a headache, and maybe bring about an onslaught of fainting.

And yet.

"Which one of you is the real Harry Potter?" Almost as soon as he had finished his question, ten voices answered in perfect unison-almost as if they'd practiced beforehand.

"I am."

McGonagall buried her face in her hands.

"Would the real Harry please stand up?" Again, in unison, the ten arose, nine being careful to mimic Harry's mannerisms.

After some consideration, he decided it would be less of a headache for himself if he simply sent Harry-all ten-to class. Without making the announcements, he stood and left to search out a headache reliever.

Hermione thought it was rather disconcerting to see Harry looking at himself, several times over. Somehow, they seemed to come to some kind of decision, and with one quick swig of Polyjuice followed the real Harry out of the hall and to his first class.

Potions was first on the agenda. As they walked in a tight cluster, they agreed to mimic Harry's every action as closely as possible. Even if it meant blowing up cauldrons.

Snape entered the classroom to see ten Harry Potters seated, nine looking overly innocent and angelic. Hands folded over books, bags neatly tucked under the desks and writing supplies perfectly arranged.

For some reason, it looked to Snape like those quills and inkpots were mocking him. Ready to leap off the desk and attack at a moment's notice.

The tenth Potter sat as far away as he could without actually being in Slytherin territory.

The rest of the class trickled in, no doubt whispering about this latest stunt.

Grudgingly, Snape gave the orders for the class to begin brewing Sleeping Draughts. It was simple enough, and surely it couldn't be messed up.

To his horror, the Potters quickly arranged themselves, scattering around the room in their pairs. Now he wasn't sure of which might be the real one… Damn it to all hell.

He would simply have to be sure he didn't address Potter by name.

Each Harry was doing the potion perfectly. More insult to injury, as it meant he couldn't realistically sneer at him for botching up. Probably they were operating under Polyjuice, which meant it'd be a while for the potion to wear off and even then, they probably knew it took an hour before wearing off.

Eventually the class ended and he retreated to his office to down a quick headache reliever.

McGonagall had somehow managed to forget that there was an explosion in the number of Potters currently in the school. Thus, when they trooped in with (mostly) cheerful smiles and bright eyes, she felt her heart sink to somewhere around her kneecaps.

She could do this. She could, she really could. It just meant avoiding using his name at all.

Unfortunately, the absolute silence radiating from Potter's corner (they were all gathered as closely as possible) made her nervous. She watched and listened with some apprehension as they settled in to transfiguring blocks of wood to carved ornaments.

After half the lesson had passed, one Potter raised his hand to ask a question.

Evidently this was a cue, because the others quickly raised their hands too. Giving them her Death Glare O' Doom, she turned to the one she thought had been first to raise his hand.

"Yes, Potter?"

Somehow the ten of them managed to ask precisely in unison, exactly how one was supposed to pronounce the incantation.

Upon returning to her desk, McGonagall conjured a small clock and watched avidly for the remainder of the lesson.

At lunch, the boys clearly hadn't stopped taking the Polyjuice yet. Their numbers had yet to diminish, as there were still all ten.

Several staff members began to hallucinate there were even more. Sprout could've sworn she saw thirteen or fourteen. Flitwick and Dumbledore, meanwhile, were creating a betting pool on how much longer the school would be hosting multiple Potters, while Pomfrey worried that an increase in Potters would mean an increase in hospital activity.

Lunch was reasonably peaceful, until the arguing began. At first, no-one even registered it. It could've been someone disagreeing over a homework answer. From there it escalated. All ten were arguing over who the real Potter was. For the first time, McGonagall felt a pang of sympathy. One of them obviously was Harry, but until the potion wore off (or they stopped taking it) there was no way to prove it.

Lunch finished, and Sprout headed off to her greenhouses. To her horror, she realized that she had Harry's class now. Time for the ten terrors.

Mercifully, they were rather subdued and created no mayhem, which may have been a side effect of the constant Polyjuicing today. Before she had left the Great Hall, Dumbledore had assured her that the prank would, undoubtedly be ended by the time classes finished for the day.

He was wrong. After Herbology had finished the ten Harrys returned to their common room, each intent on as much mischief as they could.

By dinner no-one was any the wiser as to which was the real Harry, and they were still scattered around the castle. It was rather worrying.

Dinner passed uneventfully, with the exception of a much smaller argument over who the real Harry was. The staff hoped it would be an end to it, and McGonagall headed to the common room to check up on her students. To her relief, there were now only seven Harrys, and one whose hair was slowly turning red.

By midnight, the Gryffindors were all back to their usual selfs, and Fred and George decided to stay up late to plan their next mission.

At breakfast the next morning the entire school was relieved to see only one Harry Potter.