It all started that one winter's day. Harry Potter watched the snow falling gracefully down over the window, masking the images of the Quidditch players beating each other to death on the field below. He was the only one in the common room today, save for Hedwig, who had been trying to gnaw off one of her legs for some time now in an attempt to use it as a lockpick, as Harry had been so consumed with watching the snow he had forgotten to let her out today.
Suddenly, Harry felt a malevolent presence behind him, as if someone had opened a window from the Forbidden Forest, as the same smell of the rotting corpses of unfortunate first-years violated by the Whomping Willow could be felt in the air. He turned around to find the source of the stench, only to find a bizarre creature heralding him. It was garbed in simple but elegant black robes rimmed in gold. It wore an inverted pentagram in a golden necklace like some sort of bling. It took the form of a handsome young man with raven-black hair and glimmering golden eyes, but underneath the robes Harry could see a glimpse of cloven hooves and the makings of tiny horns beneath the hair, barely noticeable under the enormous G-UNIT beanie he was wearing, but noticeable to Harry as he had EPIC GARY-SUE SIGHT.
It was Satan.
"HEY, HARRY. WANNA BUY SOME DRUGS?!" Satan screeched with all the elegance of a man getting his chest hair waxed by a red-hot branding iron. Despite the horror of the sound of it, Satan's voice was irresistible. To everyone else, that is, who hadn't seemed to have noticed that Satan was Satan. To everyone else he was an ordinary student with a graceful voice and the ability to pull whatever he wanted out of his hat, which they chalked down to awesum magik skillz. They also didn't seem to notice that he had hooves, probably because anyone who saw them wouldn't survive the ensuing kick in the head. No-one noticed this, either, and the corpses were dragged away to some random corner where Peeves probably did nasty things to them.
"Fuck you, Satan." Harry responded, turning back to the window, not even bothering to notice that Hedwig had dropped unconscious from blood loss. She was instantly reincarnated into a zombie via the aforementioned Prince of Darkness and flapped about muttering 'BRAINS' in some ancient demonic dialect.
Satan growled at Harry in a voice that would have forced Fred Phelps to join a black metal band.
"YOU DON'T LOVE ME BECAUSE!!1!" he screamed.
"...That's not a sentence." Harry replied, flipping through a copy of Playboy.
"YOUR MUM'S NOT A SENTENCE!"
Harry's eyes flashed with all the power of an electric generator being run by Zeus on a particularly bad day.
"DON'T YOU EVER INSULT MY MOTHER!!" he cried, whipping his wang- I mean wand- seriously I meant wand- don't look at me like that- out of his robes.
"Meatballius Soup!" he barked as Satan was immediately turned into a beef porterhouse steak, well-done, with trimmings of oregano around the edges.
"YOU BASTARD I'M GONNA TELL MY MUM"
The now slightly meatier Satan somehow managed to drag himself off, crying while leaving a trail of herbs on the floor.
"This…is going to be a long winter." Harry growled, turning to the table beside him and taking a long swig out of a bottle of vodka that had somehow appeared there.
He passed out subsequently, leaving a rather angry Hedwig stuck in her cage jumping up and down on one leg.