Author's Note/disclaimer: I do not own How To Train Your Dragon or the song "Black Unicorn." The former belongs to Cressida Cowell and DreamWorks, the latter...I don't remember, but it's not mine.

I am he that knocks on your windowpane;

I am he that stalks the night;

I am he with silver shot through my mane;

You'll dream of me with fire-eyes bright;

If you ever meet me standing there

You'll wish you were never born;

I'll seize your soul and strip it bare

I AM THE BLACK UNICORN!

...

My horn is forged of silver fire;

My shoulders bear leathern wings;

I am the nightmare of your own desire;

I am the song that the Devil sings;

Hellfire dancing in my eyes;

My coat is as black as coal;

Mortals are so quick to hypnotize

AND THEN I MERELY TAKE YOUR SOUL!

...

Teeth sharp as daggers cooled in the snow

And hooves that burn through the ground;

Follow me not where I lead you to go

For then your soul will be devil-bound;

There is but one who rides my back

And keeps his soul ever free;

His heart is cold and will not crack

AND HE IS AS CURSED AS ME!

...

I am he that knocks on your windowpane;

I am he that stalks the night;

I am he with silver shot through my mane;

You'll dream of me with fire-eyes bright;

If you ever meet me standing there

You'll wish you were never born;

I'll seize your soul and strip it bare

I AM THE BLACK UNICORN!

Everyone at Berk Ranch knew that song. Everyone knew that of the five varieties of unicorn, Black Unicorns were one of two that were unbreakable. They and Frigid Unicorns were swift, maneuverable, and very strong; they could take a rider anywhere (whether the rider wanted to go or not) and could pull against the bit far stronger than any other. Frigid Unicorns could freeze the balls off a man if his drawers weren't adequately padded against their coats; Black Unicorns were worse, charging into the Woods That Howled with whoever was unlucky enough to stay on top. No one knew what happened after that, because no one who had gone in there atop a Black ever came back out again - it was said that the "howls" the woods were named for were the death cries of the Black Unicorn's victims.

Unicorns in general didn't breed well in captivity; new ones always had to be captured, from one of the many herds to run the Wilderwest. A man could possibly be forgiven for capturing a Frigid Unicorn among the others - provided he could prove he was color-blind (Frigid Unicorns were always gray-coated with molten horns, eyes, and hooves; all other unicorns had warmer coats and cooler keratin). There was no excuse for a Black, since no other unicorn's coat came nearly so dark nor their horns so light.

When Stoik Haddock saw the black beast charge howling out of the trailer, his face went so red that a great many of his workers ran for cover. The unbreakable unicorns could in theory be trained by learning their language and speaking to them with it, but nobody had the time to unicorn-whisper these days. This Black was a filled stall and an extra mouth, and for what? Bragging rights? Not a man or woman could even sit up and pose on the thing. Well, perhaps Valka - but she'd been called away on an emergency much farther North and had gotten snowed in. Her wistful emails made it clear that she'd be home as soon as the roads were cleared, but with the state of the highway maintenance that could be months.

"Really, Spencer?" Stoik demanded.

Spencer smoothed his dark hair and looked haughtily at his brother-in-law. "This one's mine, Stoik; I'll have him trained down in no time."

"Really?" Stoik's tone slid towards skeptical. None of the tame unicorns on the ranch (or that had been sold off the ranch, for that matter) had ever been Spencer's; Hiccup had more success gentling unicorns. Why Spencer thought that he could do a better job as ranch head was a mystery to Stoik.

"Absolutely! I've done my homework on this piece of enchanted horseflesh..."

Now that Stoik had to see to believe.

"...And I am completely ready to handle anything this baby can dish out."

Stoik rubbed his forehead. "Fine, but until it can take a rider its room and board are coming out of your salary."

That stopped Spencer short. "Ah, erm..."

For a moment, Stoik thought that he could order the Black released. Then Spencer regained his equilibrium.

"Deal!"

It was a nice thought. The man had enthusiasm, at least. "When can I expect to see your results?"

"I'll be riding him by the end of the week!"

Even if Spencer had any skills at taming unicorns, he couldn't have pulled that one off: there were only three days left in the week. It took far longer than that to take a wild unicorn, put a saddle and bridle on it, and convince it to carry a rider without trying to kill him or her.

"Good luck with that," Stoik muttered, rubbing the bridge of his nose. As he turned away he heard the unicorn snap at Spencer's hand.

"I'm going to call you...Night Fury!"

Night Fury quickly became the bane of Spencer's existence. He would stab and kick whenever anyone tried to pet or curry him, he kept pulling his saddle blanket off and even trampled one to smoldering pieces under his fiery hooves, and he made it very clear that if his "leathern wings" were actually functional as more than steering aids he would fly away and never come back. Three days passed, then four, and very little progress had been made.

Hiccup could find it in his heart to feel sorry for the Black. Night Fury had never asked to be taken away from his old stomping grounds, or to have saddles and bridles buckled onto him. It was against his nature - against most ungulates' natures, surely - to carry weights on his back: what if it should be a predator up there? Big-cat griffins hunted unicorns, and so did wendigoes; both struck from above to sever the spine. It wasn't contrariness, it was very practical on the part of the unicorn. You didn't win his trust by jumping on his back - or, for that matter, by subterfuge: he would recognize a stalking predator from dodging werewolves in his natural environment.

No, it would have been better to put Night Fury with other unicorns that had already been mostly tamed, and let him get accustomed to the presence of humans by observing how the other unicorns handled their presence. Then, when he needed the humans' care himself, he would be more inclined to accept their voices and hands without a fuss. It was too late for that now: he'd been put in what was nearly equine solitary confinement, and he was now so badly spooked that he would likely start a fight if he was put with the others.

What he most needs now is a friend. Hiccup watched Night Fury pace restlessly in his own little enclosure and wondered if they had any unicorns able to handle a wound-up Black. Perhaps one of the Lowland Unicorns; they were the slowest, but the most enduring and most forgiving. His friend Fisk rode one on occasion...come to think of it, his dad's best friend had a rather large and lazy one. If either of them was willing to let their mounts keep this poor skittish creature company...

Hiccup's thoughts jarred to a halt when he realized the hoofbeats had stopped. Looking up, he saw that Night Fury was staring at him from a few paces away with trembling wings and turned-back ears.

Don't move...by all accounts, although all unicorns had better vision than horses, Black Unicorns couldn't see very well in bright light (which was probably one reason why Spencer was having such trouble). Night Fury would have an easier time establishing if Hiccup was a threat or not if the boy held very still.

Night Fury started forwards, one slow step at a time. His pale eyes were fixed on Hiccup, measuring the slight stature.

Hiccup carefully hefted himself up on the fence, putting his head closer to level with the unicorn's as the distance was closed and taking care to keep himself on his side of the fence. He kept his hands to himself - for now. The unicorns always told him when they were ready to be touched.

Finally, Night Fury brushed his nose against Hiccup's chest. He pulled a deep breath, drinking in the boy's scent; perhaps he was associating it with a nonthreatening creature, since Hiccup hadn't tried to grab his head or jump on his back. His ears flicked forward partway, and he drew his nose down the front of Hiccup's shirt.

Hiccup finally dared to lift a hand. Slowly, carefully, he brought his fingers level with Night Fury's horn (which was aimed right at his neck) and gently nudged it to one side. It burned his fingertips a bit, like a live wire with a low current; other unicorn horns weren't like that.

Night Fury's ears flicked, and he focused his eyes on Hiccup's face for a moment. Then, slowly and deliberately, he turned his head away.

Hiccup wasn't disappointed; particularly jumpy unicorns took time. This was admirable progress, that when he touched the horn this Black didn't try to run him through and didn't run to the other end of the enclosure. He was simply walking away - along the fence, so that if Hiccup cared to he could probably hold his hand out and let Night Fury's movement turn it into a stroking gesture.

He didn't care to. That was taking things too fast.

Suddenly a hand closed on his belt and flung him over the fence. He tumbled through the air and landed on his back, his legs snagged on -

Night Fury's wings.

Oh, no...

Hiccup was on the back of a Black Unicorn. An untamed Black Unicorn. With no saddle, no bridle, absolutely nothing to hold onto - and he'd never learned how to ride bareback. He had only about a quarter of a second to realize the horror of his position, and no time at all to think of a solution...

Small wonder that people thought the Black Unicorn was the Devil's own steed, if they had seen one trying to rid itself of a rider; even less of a wonder, had they found themselves in such a position and managed to escape with their lives. The moment Night Fury felt the slight but sudden weight on his back he went mad, bucking and thrashing in ways that were like a horse but were simultaneously far beyond what a mere horse could do. All that kept Hiccup from getting stabbed was that the unicorn's very build prevented it from striking its horn too close to its own spine, and he was laying flat on that very spine. There was a terrible, explosive crash as white-hot hooves kicked through the fence - and then, realizing that the way was clear, the Black ceased his bucking and was out the hole like a shot.

The last glimpse Hiccup had of the ranch that day, craning his neck to look upside-down, was of a burly dark-haired teen staring after them with his mouth hanging wide open in dismay.

Scott. You lout, what did you think was going to happen? Hiccup didn't entertain any thoughts that the other boy was regretting throwing him on a unicorn's back; not when he'd done the exact same prank several times before, both to Hiccup and to the twins that visited. No, Scott was only regretting that his father's prize Black had broken free, leaving such wreckage in its wake that even more money would have to come out of the Jorgenson salary to fix it.

Then Hiccup focused all of his attention on staying on, and he prayed that at some point it would obviously be safe (at least relatively so) to unhook his legs from Night Fury's wings and dismount. Just now, they were moving way too fast.