This is inspired by '150 things I may not do, written by: MMcgonagol' (which belongs to thepotterhead-directioner4eva.) and 'How rules are made' (by gredandforgerock)
Disclaimer: I don't own Harry Potter
Seamus sighed, he was bored ever since his last big prank (which turned out to only be able to be reversed by Harry…not his fault honest). McGonagall had been watching him, clearly expecting him to do something again. He threw himself onto his bed with a sigh. Dean looked at him with an eyebrow raised, Harry looked over with a smirk. "Bored?" they asked, both their voices as mocking as the others. At his nod, they grinned and lent over to whisper something into his ear. A slow grin spread across his face.
A few hours later
Ron Weasley stormed into the common room. He did a dismayed double take when he noticed a small terrified looking second year sweeping the floor with Harry's firebolt….
Hermione slid to a holt in front of the library doors, horrified by the notice on the door "the library will be closed for the foreseeable future"….
Professor Snape stared at the small innocent looking present sitting on his desk, after checking for any spells he tore off the Christmassy paper. His shout of rage could be heard in the great hall, he stared at the bottles of shampoo sitting there. He was so shocked that he failed to notice that every single potion's label had been changed to read 'Drink me'…
The house elves stared in horror…someone had gotten into the student laundry and now all of Draco Malfoy's clothes now proclaimed 'All I want for Christmas is a pimp cane like my Daddy's'…
Several Hufflepuff first years were found trying to ward Slytherins off with crosses….
Professor McGonagall stormed into the great hall, looking for the obvious culprits. Stopping and staring at the first year Gryffindors and Slytherins who had replaced the conventional Christmas tree decorations…
Harry Potter grinned attempting to look innocent as an enraged Professor Snape stormed passed him just as he was handing Peeves Hermione's 'borrowed' prefects badge…
Dean Thomas was caught attempting to slip catnip into Professor McGonagall's things…
Seamus was the last to be caught and that was only because he walked into Professor Flitwick and leaving a large red mark from the paint….
Well this is just a random idea that came into my head after reading both of those two, sorry if its worse then even I thought….