The lonely Indiana road rippled as the fabric of the world shook and wrinkled around him. When the world went still, Castiel knew immediately that Jimmy Novak was gone, the anchor of his humanity slipped away. The blades of grass his Father had designed--or perhaps simply sketched out roughly in an empty corner of His mind--grew shockingly high over Castiel's head, and the rough gravel on the shoulder of the road loomed too large, sharp-edged, hurting his feet.
Castiel lifted one foot and peered down at it, at the pink pads with dusty white fur poking all around them. Paws, he corrected himself. The gravel hurt his paws. Castiel felt the echoes of the Anti-Christ child in the transformation of his shape, but it wasn't entirely negative. He took a delicate step and stretched out the lines of his new body, ducking his head, lifting his back end in the air, unfurling his tail toward heaven.
He thought about Dean Winchester, closed his eyes, and when he opened them he was crouched on the black surface of a parking lot, the shadow of something huge looming over him. He leapt up onto the thing, and found himself exploring with his paws the vehicle Dean called his baby. The metal was warm in the morning sun, but a small sound of movement in the grass at the edge of the parking lot drew Castiel's attention, his ears swiveling and then his head. It smelled like rabbit to his cat brain, and it felt like an enemy.
His stomach growled, and without meaning to he thought of the hamburger he had consumed, the ground flesh of the cow. His new small body could never manage to acquire a cow, but Castiel couldn't stop thinking about the bright red color of the flesh, how moist it had been, with bits of liquid blood that his tongue ached to drink. He jumped down from the roof of the Impala, landing soundlessly, then moved towards where the rabbit sat. He slipped underneath other cars, twining his body around the wheels, crouching lower and lower to the asphalt as he approached the grass.
The rabbit was only a few feet away, its ears perked up and twitching but its body still. Castiel went still as well, cultivating the kind of calm he had always known in battle. The energy in his body collected and tensed in his back legs and then he sprang.
Claws in flesh. Fur in his nose. Tiny cries in his ears. His whole body locked in battle. Finally, his teeth found their mark and he shook his head hard. The rabbit went still, the panicked movements of its body translated into black smoke that poured out into the air. Castiel paid no mind to the smoke, with the taste of blood in his mouth even better than the hamburger. He wrestled with the rabbit's body, shredding its stomach with his back claws, and then ate until his own stomach was round and full.
He closed his eyes in pleasure, thought of Dean Winchester. Inside the motel room, he stepped delicately onto Dean's chest and looked at the sleeping man, his face so large and strange from this new perspective. He licked the last traces of blood from his paws and whiskers and relaxed into the warmth coming up from Dean's chest. It was better than the roof of the car, with its sun heat battling cold air. This was body warmth and breath heat, and it only grew warmer the longer he sat.
Dean did not understand. Neither did Sam, but Castiel felt that Dean could understand if only he would listen. Castiel sat staring at Dean, trying to send his thoughts into Dean's brain, and he used his new voice but still Dean did not understand. Castiel's feline tongue had many uses--cleaning himself, lapping up blood, scraping pleasantly against the salty taste of Dean's skin--but it wasn't able to talk as men did, nor as angels.
He protested when Dean took him into a place that smelled of desperation and separation, but Dean just handed him off to a woman who put him in a cage and locked the door. The cage had nothing on the bindings of heaven or hell, so Castiel moved through the metal bars. He touched his head to some of the creatures who shared his form, tried to tell that he understood what it was to be abandoned by the one who gave your existence meaning.
The inhabitants of the cages felt not so unlike the humans in their various living spaces--some of them curling patiently around their hope; some lying in their waste, limp with despair; others crackling with barely-contained rage. In one cage, Castiel's fur all went on end, his spine shocked stiff at the flicker of knowledge that told him he was nose to nose with an angel from another garrison. She breathed out a hiss and then sat down, calm and still.
Castiel took a step back and blinked his eyes, but it was clear she had no wish to communicate further. Like him, she could leave any time, and her orders were not his business. He thought of Dean Winchester and traveled to another town, another motel bed. The demons he encountered were not much of a challenge, and chasing them was a kind of joy. In those moments, he had no thoughts of his absent Father, no worry about how the apocalypse would be thwarted; he became pure focused energy, seconds stretched into minutes, and the bursting tang of blood and meat torn from crunchy bone.
And yet he found that his new shape was not without its risks. He was crouched in the bushes outside of a house where Dean and Sam were interviewing a woman. Castiel contentedly gnawed on the chewy ligaments of his latest kill when a tomcat easily four times his size came tearing through the branches. Castiel puffed his fur to make himself as big as he could, as he hissed and drew his ears back flat against his head. Still, it was as much use as a cherub raising his hand against an archangel, and the cat came closer, growling like a soul in hell and clear in his intention to steal the remains of Castiel's meal.
Castiel stepped back and hissed one last time before flattening himself and scrambling under the hedge and out into the open. As he heard the big cat chasing him from behind and familiar human footsteps ahead, he took off running and launched his body through the air to latch onto the sturdy fabric covering Dean's legs. He meowed at Dean, tried to tell him to run to the Impala, but as always Dean didn't understand. Castiel climbed higher until he could drop down into the shadowy warmth of Dean's jacket. He clung to the fabric with his claws and curled against Dean's stomach, letting the frantic race of his pulse slow down even though Dean wouldn't stop jumping around and shouting profane words at the tom cat.
After that, Castiel's days became easier. Dean and Sam stopped leaving him in places with cages and doors, and he didn't have to use his powers to travel through space to find them again. He hunted when they did and ate the scraps of tasty food they gave him. He traveled in the Impala and listened to them talk about his own absence, the absence of all the other angels and demons. He slept each night curled around the places where warmth radiated out of Dean's body, and he tried to ignore the fact that Sam tasted just a little bit like a rabbit.
They visited Bobby, and the big dog there barked, straining at his leash until Castiel turned to look at him. The dog whined, lowered its head towards the dirt and sat hard on his rump. This, Castiel felt, was just as it should be. He couldn't smell any demon rabbits in the area, so he climbed the steps to Bobby's front door and followed Dean inside. Dean sat on a chair in a patch of sunshine, and Castiel sat on his lap, wriggling his body until Dean relaxed and sat still.
Shortly after they left Bobby's house--or it might have been as much as a day, the way his sense of time had become unfixed--Sam and Dean stopped at a restaurant. Castiel prowled the grassy lot behind the diner, searching for the demon he'd scented from the car. When he found his prey, and leapt in for the kill, he realized that the rabbits were growing in size and maturity far more quickly than his kitten form was growing. He had no doubt that the power imbalance would eventually revert, but in the meanwhile he found it disturbing to be mounted by a rabbit attempting clumsy copulation.
He struggled in the demon's grip and eventually sacrificed a small scrap of his ear to make his escape. He curled up on the Impala's hood, where the still-hot engine warmed him from below, and licked his wounds. He would remember the scent of that demon and return when he grew larger. For the meanwhile, he would stay closer to Dean, stay safe.
When Sam and Dean's travels took them to the door of Jesse, the boy Anti-Christ, finally Dean looked down at Castiel with knowing eyes and spoke his name. One moment he was four-paws-on-the-floor, the next he was stumbling on hands and knees, looking up at the humans laughing at him. He rose to his full height and touched his fingers to Dean and Sam's foreheads, removing his existence in feline shape from their memories, returning them to the Impala at the same time.
Jesse smirked up at Castiel, but before Castiel could respond he felt a tickle in his throat. He coughed and bent forward, hacking up a tangled lump of fur, dried bits of leaves, and stomach fluid on the floor at the boy's feet.
He left then, traveling to as many places as he could to confirm that there were in fact no demons or angels walking the earth on two legs. They were instead hopping and slinking around, and none of them bore more than the slightest threat to human beings.
Somewhere Castiel had yet to find, Lucifer was almost certainly prowling the earth as a cat, growing larger every day. Still Castiel was confident that the apocalypse was averted for the meanwhile, and he recovered enough of his pride to find Dean and Sam again.
Later, when he stood face to face with Dean, inside the personal space Dean claimed to covet, Castiel couldn't help but wonder if the sweat on Dean's skin would still taste good to Jimmy Novak's tongue, the way it had to the kitten's. He imagined that the rasp of his soft tongue on Dean's stubble would be much like the rough texture of the cat's tongue on Dean's fingers. He remembered too the warmth of being curled against Dean's body, the peace of the steady rise and flow of his breath, and wondered how that would feel with both of them nearly the same size.
They had time now, with the demons in hell and the angels in heaven both avoiding earth at all costs. They had months, perhaps even years. Castiel hoped to learn many things.