"Ready to go Padfoot?" James said with a grin, rolling up the Invisibility Cloak and tossing it into some bushes where it melted into the greenery.

"You bet I am," said Sirius, grinning as well. "Wait till Moony and Wormtail find out, they'll be so mad!"

"Yeah, well, that's there loss." James said, staring around at the Hogwarts Grounds. Beautiful in the darkness, illuminate lightly by a half moon hanging above the lake. He crouched onto the ground, feeling wet grass between his fingers. Sirius did the same. Seconds later, a stag and dog replaced them.

The stag—James—strolled towards a nearby tree and rubbed his long, curling antlers against its trunk, leaving deep scratches in the bark. He sighed, which came out as a soft uurr. The velvet on his prongs always itched when he transformed.

Sirius, the large bearlike dog, woofed his disproval, before dropping his nose to the grass, which told him stories of all the people, animals, and rain had been here hours before. He wagged his tail and rolled around in the scents—pure bliss! He walked towards the tree James was still rubbing his antlers against, sniffed it at the base, cocked his leg, and peed against it. Ha! Now it was his tree! He marked it!

He yawed, stretched his legs, and woofed at James again.

C'mon, we've got other stuff to do! he thought, though obviously James couldn't understand. To prove his point, Sirius bounded for the Forbidden Forest, and James, not wanting to be left behind, ran after the dog, leaving a pile of pellets behind him.

No human (except perhaps Hagrid) could've navigated through the brush so well. They had more experience in the Forest than any besides the gamekeeper, And with eyes, ears, and senses capable of seeing every beetle, hearing every whisper of wind, and bodies strong enough to tackle the foulest of creatures (like Snape, for example) they had nothing to fear. The "boys" galloped through the trees, barking and mewling as they leapt over logs, splashed through puddles, upset homing animals, and marked the trees with velvet and piss, and having a great time at it. They were best fiends, at the best school, and life could never get better than this.

A squirrel sitting on the ground caught Sirius's interest, and he barked at the thing, chasing it as it chirped and raced up an oak. Sirius barked at it, even as it disappeared into the branches.

No Wormtail getting in the way, no Moony to worry about. Just me and James on the run for ourselves, he thought happily with a wag of his tail. It stopped in mid-twitch as his nose snagged a new scent.

He turned back into a boy, almost seventeen.

"Hey Prongs, you smell that?" James nodded his head (an odd gesture to see from a stag) and turned into his normal self.

"Snivellus? He's here?"

"Yeah, why I have no clue. Better have our wands out, you reckon?"

"Nah mate, he'll get us into trouble." James grinned, his eyes brightening with an idea. "But we can still have some fun with him…"

He whispered his plan to Sirius.

"Sounds good mate. Bit cheeky though, ain't it?" he asked as he dropped to all fours again.

"Of cour—"James tried to say as his mouth bulged into a muzzle. He pawed the ground with his hoof as Sirius padded towards that overwhelmingly rotten smell.

There he was, sitting on an old stump, wand in the air. The dog snorted—what was Snape doing here at night all alone, surrounding by creatures more dangerous than himself? Doing schoolwork in privacy, or something else, something he wouldn't dare do even around Slytherins…? He had to find out…

He crept up from behind, hoping the greasy git wouldn't see him. The stench became overpowering, magnified by his canine snout. Sirius couldn't help it. He coughed, choking on his own spit, and Snape roared, turning around.

"Who's there? Lumos!" Light appeared at Snape's wnad tip, contrasting with his oily black hair and eyes.

Sirius growled uncontrollably. Here was his chance to finally get Snivilleus back, for all the sneaking around, for trying to get them expelled, for stealing his best friend's love. Snape directed his wand at the sounds, only to see a heap of black hair rush at him.

"Arrgh!" They fell into a heap, Sirius biting every hint of flesh he could hold, Snape punching him and throwing curse after curse at him. The dog felt the spells hit him, burning his hide, but he continued to attack, mauling the boy bleeding under him.

Sirius couldn't remember anything that happened afterwards. He vaguely saw a stag rushing at them, its antlers separating the two; there was something about Snape running off, limping with a wounded leg, of James flinging him onto his back, and being at the edge of the Forest. That was where Sirius woke up.

James, human again, was standing over him. "You alright Padfoot?"

Sirius groaned dully. He was sore allover, still feeling all of Snape's bloody curses. He rose onto all fours shakily, as if he was just a pup learning to stand.

James stroked his back. "Why'd you do that Pad? He had a wand, and you know that git'll do anything to skin us. Why'd you attack? I thought we were just gonna scare him, make him feeling surrounded by animals."

Sirius tried to say "'cause of everything he did," but couldn't. He tried to transform to talk, but found his mouth unable to work.

"C'mon Sirius, it's Monday, we gotta get up to the Castle. Change back."

Sirius tried to change back, he really did, but couldn't; he was weak, tired, and hungry, and couldn't stand, let alone transform. Try as he might to throw away his dog body, he couldn't change into his human shape.

And he never could again.

Thanks everyone, will be grateful for reviews. This fanfic is a combination of Harry Potter and the true story of Hachiko, the world's most loyal dog. A google search will tell you everything, and it's a smple story, but I won't mention it here for those that't don't want spoilers. Hope you enjoy!