Disclaimer: HP and associated characters not mine. More's the pity.
Inspired by another fic I found… possibly on Azkaban's Lair. I can't remember what it was called or who wrote it. The lines which fed the plotbunny are at the end. A direct parody of 'The Night Before Christmas by Clement Clarke Moore. If anyone knows who wrote the other fic, let me know and I'll gladly credit them.
'Twas the night before Christmas, when all through the dorms
Not a student was stirring, save for four male forms.
They'd spent all the evening planning with care
The prank that would give the cat dual-coloured hair.
Its owner was snoring all snug in his bed,
While nightmares of Marauders danced in his head.
The boys in their cloaks, with fish in their hands,
Were setting a trap in the owlery stands,
When from outside the door they heard the patter
Of footsteps from Filch's champion ratter.
They sprang to the door, but their actions were rash-
The stands came down with a bang and a crash
The cat disappeared when they fell out the room,
It went to fetch Filch, to deal out their doom.
They hurried away from the scene of the crime
Laughing, covered in feathers and grime
They fled to the kitchens to eat up their fill
Thankful that Hogwarts remained peacefull and still.
When one of them noticed through a crack in the wall,
The glitter of lights, which caused him to fall.
The others all laughed, but soon settled down
When they realised their friend wasn't playing the clown
They searched the wall, and heard through it a clatter
Like the sound of elves working, and also a chatter
They found the secret switch and opened the door
To see a vast workshop on the far-below floor
The House-elves were working with fervour and speed
Wrapping the presents the students would need.
And throughout their midst danced the headmaster himself,
Looking much like a skinnier Jolly Old Elf.
All clad in red with his long beard of white,
Dumbledore danced, looking high as a kite.
The boys took one look and knew they should leave this alone
And decided to close the door made of stone.
But they heard him exclaim, ere they ran out of sight
"Happy Christmas to all, and to all, a good night."
Inspiration: "Padfoot was completely covered in snow and twigs, including two that were sticking up rather comically above his ears. "Padfoot the black-furred reindeer?" Remus chuckled. He reached down and plucked the twigs from the thick fur.
Padfoot transformed back into Sirius and Remus took a step backward when he realized how close they were standing. "Ha, ha," Sirius replied. "And Dumble-Clause has house elves make the toys right?"
"This is starting to sound like The Night Before Christmas, Hogwarts Style," Remus laughed."