Quoth the Raven...
Severus Snape muttered an incantation and shifted slightly. The air around him rippled visibly as he transfigured into his animagus form. Stretching his black wings and giving the equivalent of a shrug, as he settled once again into the familiar shape, he regarded the open door, and then the desk next to his canopied bed in the sixth year Slytherin dorm. If he attempted to leave the dorm with a quill in his beak, he would certainly be spotted by his classmates. The blasted turkey quills were too light in their grey and white stripes. And his precious ostrich feather quill would catch too much air... In truth, any quill would interfere with his flight dynamics. Pecking disconsolately at the blotter, he yielded to necessity and picked up the abomination known as a biro.
Taking a moment to listen, he determined that the corridor immediately outside the door to the room he shared with four other snakes was empty. Rustling his feathers once more, to remind himself he was a raven, not a wizard, at the moment, he leapt off the desk and flapped as soundlessly as he could out the door. From there, he gained altitude, until he was flying sufficiently overhead that he was hidden against the high, dark rafters of the Slytherin common room. The difficult part was getting out of the dorm altogether. For that, he would have to be both quick and nimble. But first he had to wait for some student or another to open the door.
While he waited, he took some pleasure in contemplating the possibility of allowing himself to... drop some droppings... on the unsuspecting heads and parchments of select individuals below him. But that would cause them to look up. He would have to gain satisfaction that way another day - perhaps while everyone was at Hogsmeade next weekend. Finally, one of the fifth years threw down his books, stretched, and said, "I'm all for raiding the kitchens, getting some food. Who's with me?" When sufficient volunteers for guarding, carrying, and scouting had raised their hands, and orders taken from the seventh year prefect, four students headed out the door. Snape took the opportunity their exodus provided, and flew just over their heads, too swiftly to be caught, despite the hands they batted at him.
Free! The biro weighed little, and weighted him down less. His wings had strengthened in the months since he had first accomplished his transfiguration. He flew ahead of the stealthy snakes, down the passageway and up the stairs, until he reached the main hall with its tall, mullioned windows. There was a convenient enough hole in one window, too high up to have been detected by the routine maintenance sweeps conducted by either Filch or the house elves. It would be sealed over, come summer, he knew, but for now, it was his personal escape hatch. He maneuvered the biro out the window, and rested on the slated roof a moment, reveling in both the height and the fact that no one - no one - could find him here. Here, he was safe. However, he had things to do.
Resisting the urge to give voice to his freedom, lest he drop the biro and have to find it all over again, he took wing, soaring around the battlements and ramparts of the castle until he came to the window he was looking for. Open - as always. Still not quite confident of his welcome, he hesitated at the edge of the deep sill, one talon gripping the edge of the window frame. The man was bent over his desk, quill in hand, humming to himself. Under cover of that, Snape hopped over the frame and actually into the room, then paced from side to side, restlessly, waiting to be noticed - and either welcomed or shooed away.
In his impatience, he squawked - and promptly lost the biro, which fell from beak to sill and rolled off onto the floor. That had the benefit of catching the ear of the old wizard, who looked up. His eyes crinkled with that damnable twinkle he always had. Were he not a raven, at the moment, Snape might have sneered. As it was, he merely looked at the man sideways, then paced a circle, just for the pleasure of turning his back on the man.
"Ah! Severus! There you are. Well, come then. We have limited time, much as I enjoy your company, and much to do. Please - do take a seat. Unless you would prefer your biscuit in this form?" He cocked his head at Snape, assuming a falsely innocent expression.
Annoyed, Snape shook himself, rattling his feathers. The air rippled around him again, though in a much smaller locality than before, and in moments, where there had been raven was now raven-haired, beak-nosed, Slytherin student whose feathers were nonetheless ruffled by the older man's... humor.
"Headmaster," he said, dipping his head.
"You have your supplies?" Dumbledore said.
"I'm rather shy of pockets, as a raven," Snape pointed out. "Though I did bring..." He patted his robes as if looking for something, pulled out his wand, and said, "Accio biro!" The pen flew from where it had landed, under the window, to his hand.
"Ah! Fine invention, the biro," said the headmaster, "Although I'm afraid I prefer the old ways. Come, come, Severus. Have a seat. Now. Tell me. How do you propose to modify your previous experiments on the wolfsbane potion?"
Snape slowly took the seat Dumbledore indicated, as if reluctant to cooperate, hiding his eagerness. Dumbledore shoved a bit of parchment across the desk. Licking the end of the biro automatically, Snape began to set down his annotations, while Dumbledore hummed in approval, watching the dark head bent low over his desk. After a moment, he glanced to the side, and made eye contact with Fawkes, his phoenix familiar. A question passed from him to Fawkes, who bobbed his head twice, for emphasis, and trilled a soothing tone. Dumbledore smiled, and looked back at the dark raven in front of him, sure, now, that the prophecy only he knew about was indeed about this young boy.
It was going to be all right.