Excerpt:

Taken from approximately chapter 5, his first change.

The tightness in his chest, the thing that made it hard to breath, pulsed. It throbbed and beat inside of him like a living thing. He gasped and fell to his knees. He felt sharp stones beneath him. It was a thing inside of him that wanted out, and he feared he might burst. It was a flame that seared him, and a scream at the back of his throat. It was more than he could bare. He threw his head back, he gasped for air and he tried to let it free. He screamed but nothing came out. He screamed, but howled instead. The flame became a blaze, white hot and terrifying. It surrounded him, consumed him, and burned his mind away. It changed him.
It hurt. It hurt in ways he had never imagined possible, as his body tore itself apart. Bone and sinew, skin and muscle, all gave way. He was shattered and twisted, broken from the inside and reformed. Claws and fangs from nails and teeth. It hurt, but he was distant from it as well, as though he were suddenly a guest in his own body. His own body which was clearly even, no longer the same. He didn't even notice as his boots ripped apart, making way for wide paws. Fur, white as polished marble, covered him from the tip of his muzzle to the tip of his tail. The pain subsided, but his mind still swam. He felt drunk, or high, like the little red pills. The world was sharp around him in the most distressing way. He fell to all fours, and felt comfortable. He howled again, and this time it resounded, echoing across the valley. -Monster?- He could smell her, he could smell her blood, and he could smell the metallic sweet tang of the powder that burned in her lungs, the rot. He could not think. He felt awash in himself, in something that had been himself. -Give in!- He could smell the trees, and the wind and knew it would not rain for days, and knew there was something hiding close by, that it was terrified, and he could catch it. -Run!- And he was running again. This time he leapt across the rocks, wide paws and thick legs launching him in mighty arcs across the thickly wooded mountainside. He ran on all fours, and he ran on two like a man, but either way whatever monster he had become, he was strong! -Hunt- Twice he leapt to lead it, running it along a course. He could smell grass ahead, warming in sunlight, a clearing. The rabbit scampered across the opening and panicked, but before it could change course he was on it. -Eat!- He felt it in his jaws, his muzzle across it's throat, there was a moment of fluttering heartbeat against his tongue, before he bit. Bones crunched, and he tasted the copper salt of hot blood. He threw his head back and bit again, crunching bones, fur and all as he gulped it down. He licked his chops, still hungry but momentarily sated, and looked for the first time down at himself.
He panted, breathing heavily, and he could see his chest heaving even under the thick white pelt. His arms were long, strangely so, although the muscles knotted and roiled as he flexed. His hands were a strange mix, like an overly extended paw, or a hand with pads and claws. His feet were wide but his ankles lifted high, they bent like a dogs. He was naked, save or the fur, though his crotch was covered in a heavy protective curtain of fur. His tail, he noted moved mostly without thought, helping him balance as he turned about trying to get a better look at himself. Reaching up he felt a long muzzle, and pointed ears high on his head. They flicked and turned as he looked around. "I'm dreaming. A nightmare." He thought. Impossible. Everything was, in so many ways impossible.
He sniffed the air, and caught again the scent of her blood. Silver, broken on the rocks. He loped back along his path, fighting not to be overwhelmed by the sensations of the forrest around him. The sounds, of the forrest, and even the town below were distracting. Each one he could place exactly where it came from, he could guess how far away. And the smells. A thousand things he had never smelled before, and as many more that he had but seemed suddenly new and meaningful. And around it all, the draw, the hunger. Instinct dragged at him, begged to hunt, to feed. But he came to the rocks, and to her, and silenced it all.
He gathered the scraps of what had been his cloths, and than he gathered her. He lifted her easily, cradling her in on arm like a sleeping child. He was huge, he realized, half again his usual hight. Down the hill he walked, thankful for the claws that tipped his wide foot-paws as they dug into the trail and kept him from slipping. She grew heavier and heavier, until he had to use both arms to hold her up, his shredded cloths dangling below her. By the time he could see his car he was sweating, and the gravel cut into his bare feet. The hunger was gone, and in its place was a vast exhaustion.