Harry first realized something was amiss when he sat up on the first day of Christmas vacation. As usual, he had opted to stay at Hogwarts rather than return to Privet Drive. He had survived enough Christmases of presents marked "Duddykins" overflowing from the living room into the kitchen to last him quite a while. Ron and Hermione had both invited him to come home with them, but Harry had declined. He liked his friends, of course, but it was nice to have a bit of time alone, especially as they had been bickering even more often lately.
After the routine yawning and rubbing of eyes, he blinked down at his red-and-gold 'Gryffindor Guts' T-shirt. Or what had been his 'Gryffindor Guts' shirt when he had gone to bed. It wasn't red-and-gold anymore, and it didn't say 'Gryffindor Guts' either.
The crimson fabric had turned green, and the formerly gold letters were silver. Harry attempted an impossible act of contortion to read it before the thought crossed his mind to take off the shirt. Well, morning had never been his primary thinking time, he reasoned with himself while removing the offending garment. 'Slytherin Savvy,' read the shining words.
"Malfoy," Harry muttered aloud. Who else could have done it? Well, he couldn't think of a way Malfoy could have done it either, but it had to be him. The snotty blonde had been as sarcastic and nasty as ever this year, and he was staying over vacation too. Harry swung his legs over the edge of his bed, only to find that his black silk boxers had changed to dark green. Well, that meant that it had to be a spell on the original clothes, rather than different clothes altogether. Malfoy would never have removed Harry's underclothing without...
Harry quickly checked inside the boxers. Everything seemed to be intact. A spell on the clothing, then.
He knelt in front of his trunk and undid the latches, dreading what he would find inside. His worst fears were confirmed as he opened the lid. Every single article of clothing, Gryffindor colors or not, was now green or silver. And that wasn't all. Up until this point, Harry had merely felt shock and annoyance, but he could sense the anger boiling up inside him as he lifted out his most treasured possession. His Firebolt.
The wooden handle was no longer naturally brown. It was the glossy hue of rhododendron leaves, accentuated by the metallic sheen of the twigs, which were unsurprisingly silver. The 'Firebolt' emblem near the end was the same color.
Harry stayed where he was for several minutes, staring at his broomstick. Then he gently set it back into the newly Slytherin-esque contents of his trunk, and closed the lid. He stood up, left his room and stepped slowly barefoot down the stone steps. Seamus and Ginny were the only people occupying the common room. If Harry had been in his normal state of mind, he would have wondered why Ginny hadn't gone home with Ron, but as it was he stormed right past her and said to Seamus in a low voice (unnecessary in the silent room), "I need to borrow some robes."
If Seamus was taken aback at the demand, he had the sense not to show it. "Sure, Harry." He led the way back to their dorm, fished out a set of robes from his trunk and handed them over.
"Thanks." Harry took the robes and shrugged them on over his altered pajamas, all the while holding back the bubbling rage that threatened to spill out.
"What... happened?" Seamus inquired tentatively.
Seamus didn't do anything, don't yell at Seamus, Harry told himself. "I haven't a bloody clue. I woke up ten minutes ago and found my trunk looking like it was owned by some sniveling mushy-brained asshole of a Slytherin."
"How could a Slytherin get into Gryffindor Tower?"
"I don't know, Seamus! I'm going to find out, though. It's Malfoy, I know it is. I'll pin the smirking little maggot to the wall and strangle him until he changes it all back!"
A grin spread slowly across Seamus's face. This was going to be good.
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Five minutes before Harry's homicidal declaration, Draco Malfoy lathered shampoo into his light blonde hair. He was thinking about the fact that Potter had stayed at Hogwarts for the holidays, as usual, and contemplating ways to make the Gryffindor's life hell. The hot water rinsed suds from his head. Draco's mind was too focused on mischievous charms and Zonko's products to notice the slight burning sensation on his scalp.
After applying conditioner and several straightening, drying and styling charms to his gleaming tresses, the cocky Slytherin sashayed around the bathroom, pausing in front of the mirror to admire his lean, muscled figure.
That was when he noticed.
Draco wiped condensation from the reflecting glass, unable to believe his eyes. His beautiful hair was no longer slicked back as usual. Nor was it spiked, wet, or transformed into a mullet (not that he had expected that). It was, in fact, absent.
He touched the newly smooth and pink dome of his head, attempting to process this new discovery. What had happened? Why had it happened? Who had done the deed?
Well, he had an answer to that last, anyway. "Potter," he muttered scathingly. The Golden Boy would pay for this. Draco stormed from the room, intent upon eradicating Potter from the face of the earth.
First, however, he rooted around in his trunk for a hat. There were standards of dignity to be maintained, after all.
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The two storms of rage barreled toward each other, one from deep in the dungeons, the other from high in a tower of the castle. Frightened first years leaped aside to let them pass. Flitwick's Christmas fairies squeaked and dived into lantern brackets. Even the Bloody Baron sported an expression of surprise as, for the first time, a Gryffindor walked through him without paying any heed to the icy sensation or his even icier glare.
They clashed in the Great Hall. Draco appeared at the top of a flight of stairs, and Harry at the bottom of another. The few students attempting to engage in a quiet breakfast abandoned all hope of peace and looked on, fascinated.
"MALFOY! What the bloody hell do you think you're playing at, you slimy little piece of-"
"I don't know what you're complaining about, you underhanded excuse for a toadstool! I tell you, when my father hears about this, you'll be expelled and-"
"-always knew you were a git, but I never thought you'd go so far as to defile someone else's property in such a brazenly-"
"-what could possibly be worse than altering my physical appearance, you're going to pay for this, Potter, you're going to beg and scream for me to end your-"
Nobody noticed the youngest Weasley, huddled in a corner, shoulders shaking in uncontrollable mirth at the scene unfolding before her. Harry and Draco were both red-faced and shrieking at each other, words only occasionally discernible from the simultaneous rants. Ginny knew that it was only a matter of time before a teacher appeared and shut down the argument, but she fully intended to enjoy it while it lasted.
One floor below them, in the Hogwarts kitchens, an extraordinarily happy house-elf sorted through his new pairs of socks and wondered why Miss had wanted him to empty a bottle of a Muggle potion into the shampoo in one of the Slytherin bathrooms.