Filch is very interesting, I think. And I think I know a way to annoy him, too… cue Gred and Forge, second only to the Marauders!

Hushed voices were discussing something in a secret passageway.

"Are you sure this will work, Fred?"

"Absolutely. Think of it as the biggest prank on Filch, George."

"Alright. Don't blame me if it goes wrong. Bestia verto!"

A few minutes later, George Weasley poked his head out of the side of the tapestry. He looked around, then whispered, "All clear, Fred."

A cat that resembled Mrs. Norris in every way padded out of the hidden passage. George leant down and bumped his hand and the cat's paw together, then quickly set off for Gryffindor Tower with a burlap bag in his arms.

Inside the bag was the real Mrs. Norris. She writhed wildly, trying to get free, but her yowls were muffled by a cloth gag and her limbs were tied firmly. George reached Gryffindor Tower and quickly slid the bag under his bed.

Meanwhile, Fred had taken the guise of Mrs. Norris for the night. He prowled around the school, completely ignoring the students who were out of bed. One stared in disbelief as Fred walked right past, ignoring the fact that the student was covering the Slytherin hourglass in graffiti. In fact, Fred gave a little nod of respect before hurrying onwards.

As the Fred-cat travelled through Hogwarts, he ripped up tapestries, scratched the fine polish on the floors and toppled torches. Finally, he reached Filch's quarters.

Filch smiled down at the Fred-cat as he picked him up and stroked his ears. "Hello, Mrs. Norris. Any students out of bounds? OUCH!"

The Fred-cat scratched Filch, hissing madly. Leaping out of his arms, the Fred-cat then proceeded to yowl loudly and use his paw to hit a Muggle-esque Red Button Of Doom.

Smoke filled Filch's office and loud klaxons went off around the school. Filch yelled and stumbled around, eyes watering. Outside in Hogwarts, a hundred students suddenly started yelling and rampaging through the school with buckets of mud and Everlasting Dust. They were all equipped with masks and voice distorters, so that they couldn't be recognized.

Several went down to the dungeons to spread filth all over the Slytherin Common Room entrance. Others simply ran around the castle, writing giant messages on walls. In the Great Hall, a message seemed to hold top priority with at least ten students working on it:

GRADUATION PRESENT TO YOU, FILCH! HAVE A HAPPY HOLIDAY!

When Filch's office finally cleared of smoke, he stumbled into his bedroom and collapsed, fast asleep. He had inexplicable nightmares of endless cleaning.

The next morning, he stepped outside his office, stared around at the destruction and screamed with frustration.

Farewell, Hogwarts graduates of Year 1995-1996!