By the Glow of the Moonlight
It was a night in Manteo, North Carolina, just before midnight and the moon was up in the sky. Trucks could be heard driving away from a certain residence, having just dropped off a certain North Carolinian from his adventure in the deserts of California a while earlier. It had been a mad day, but at last he was home, in his home town, in his home state even!
And he lay in his bed, Jimmy Hook did. Such was his status he could even make being asleep be interesting. It seemed he had got through an entire Monday without transforming, as he had been unconscious for the bulk of it. But as the clock clicked 23:57, weird things began to happen.
The window of his bedroom suddenly clicked open with a clank and a bang, the mechanism seemingly moving by itself as if cursed by magic. This will not be surprising in and out of itself, as anybody who knows Jimmy knows that strange things happen around him at the best of times. The wind rushed in, and Jimmy rolled slightly to avoid the cold.
“What...was that?” he murmured in his sleep, apparently unaware he was human again but hid under the sheets nonetheless, the weather being too cold anyway.
But things got stranger still. Just then, a raven entered through the window. How it got through the window is a mystery, given how narrow it was, but enter the room this raven did, and it looked around before squalling. Whatever it was, it clearly had mischief on its mind, as all ravens do is cause chaos and misbehave.
It soon found its victim. Jimmy proved to be far too appealing to be ignored, and over it flew, first mucking his hair about, moving strands here and there to irritate him and then plonking some in his eyes. Which were shut, so it would be more accurate to say it put some on his eyelids.
He needs a haircut, the raven thought, before it had another idea to annoy him even further. It moved over to the bed sheets, and began to move them about to try and wake him up. This had little effect, as in his half-sleep state, Jimmy simply reached forward and pulled them back onto his body. “Not...getting...cold...desert...too...cold.” His words revealed a lot about his current mental state, as he seemed to think he was still Somnambula.
Then the raven had the ultimate idea to irritate him as much as possible. So, it flew over to Jimmy’s finger, and pecked it.
Jimmy then shot up in bed. “Ouch!” he exclaimed, bringing his finger up to observe it, kicking the raven off his bed as he did so. “Shoo, you stupid bird!”
The raven squawked and flew off, laughing to itself. “I still win!” it cackled as it flew off.
Jimmy sighed as he looked at his finger. Wait, finger? “Hang on a minute, I’ve changed back!” he said. He suddenly realised he was completely clothed. The military must have given him some. His ‘curse’ had led to him needing a large clothing budget, if the shredded shirt and pants still sitting in his living room from that time he had changed into Cheerilee was any indicator. Oh well. At least stuff was cheap in the United States. It was just then he started to feel odd.
“Oh not again!” he said, looking at the clock, and seeing it was 23:57. “I was so close too!”
His skin changed to a pale gray, before fur of the same colour erupted from his body. This was followed by him gaining a tail, which grew out of his backside and hung loosely inside his pyjamas. They promptly proceeded to vanish, which was followed by his hair changing colour to a dark blue and curling around a point on his forehead.
Just then, pressure started to build up under his forehead, which changed into a raging inferno as a horn exploded out of his forehead, growing several inches out of his skull before stopping. It had moved, quite conveniently, through the gap created by the curl in his hair. To complement the horn, his nose merged with his mouth, which began to grow out of his face and gain a few inches. The result was that he now had a muzzle, which was quite a contrast to normal. In addition, his tongue became a lot thicker, which made speaking very difficult.
“Whath?” he asked, his speech almost unintelligible. “Thith doesthn’t uthually happen with my tongue!”
His teeth shifted to those of an equine, followed by his eyelashes becoming much thicker, and his eyebrows followed suit. His eyes then joined them, going yellow.
His body then began to shrink in size, becoming a fraction of it's former size, followed by his toes shrinking into his feet and the joints in his legs inverting to become those of a pony, which should have really been obvious at this point. His manhood vanished, something which this time he had full view of, and two other things replaced them.
“Well, should have sheen that coming,” SHE said, realising her voice had changed to sound like she had smoked 50 cigarettes a day up to this point. Her fingers shrank into her hands, which morphed into hooves, and her arms changed into forelegs, switching positions and the joints inverting as this happened. As her cutie mark, a heart surrounded by lines, appeared on her flank, all trace of Jimmy was gone (for this week at least).
Moonlight Raven woke up somewhere or other in Manehattan. “Wow,” she said. “That was a really great dream,” the tone of her voice never changing beyond sounding extremely bored.
“Hi there!” shouted a voice, as another unicorn galloped toward her. “I’ve been looking for you!”
“I’ve been in my bed the entire time,” Moonlight replied. “Try to be more observant.”
“I’m just happy your safe!” the other unicorn cried. "I thought you’d want to know that Rarity has more clothing on sale! I thought it would suit you perfectly!”
“Well, then, let’s go,” Moonlight finished, before hopping out of bed and heading out into the street with her sister.
Author's Note
Shout Out goes to Chrome Masquerade for guessing Moonlight Raven in the comments section of the 2nd chapter of Sands of Time! 
I'm only 1 story away from reaching 10 stories!!

Now, anyone want to guess which other Unicorn was it that appeared at the end of this story? The keyword is Sister. If anyone guesses correctly in the comments, one of y'all will win a shout out for the Author's Note in the 10th story next week! (Chrome Masquerade, you don't have to do it again since you won the first time around ^^;
)