Just as the terrified Josh was turning to run from the two werehorses, the shopkeeper blew a fine powder directly into his face. Josh inhaled the powder, coughing as he ran out of the shop. He looked back as he left the shop behind him and to his relief neither of the werehorses were following him. He kept running - through the mall and back down the streets and lanes to his house on the corner of town. As he ran, he could feel the adrenaline pulsing through him and he couldn't help feeling that his t-shirt and jeans were feeling a little tighter than normal.
After what seemed an eternity, he reached his front door. Feeling for the keys in his pocket, he furtively looked around him, to see whether he had been followed. 'The coast seems clear' he thought, as his key revolved in the lock.
Once in, he went straight into the kitchen for a glass of water. Whilst gulping down the water, he caught his reflection in the window and gasped as he noticed that his hair had grown noticeably down to his shoulders. He distantly heard the crash of the glass of water on the floor as he dashed to the bathroom to get a better look in the full length mirror. As he ran, he felt a peculiar stirring in his groin and could feel that he was starting to involuntarily get an erection.
He made it to the bathroom and took a look at himself in the mirror. He seemed to think that he looked a little bit taller than usual, but dismissed the thought as madness. 'Could this be the powder the horse man blew into my face?' he thought. As his mind went back to what he could only think was Katie, his erection grew stronger yet. 'She didn't look right' he thought. 'Her face was different, horse like and she was far taller and bulkier than normal and her legs - God, her legs were huge'. He could now feel that his erection was getting far too tight in his pants, and so he unzipped his pants and took down his underwear. What he saw amazed him.
He could swear that his cock was bigger than before and the more he thought of Katie, the more it pulsed, aching to be touched. Before he could stop himself his fingers wrapped around it. As he pushed his hands up and down its length, he could feel it pulsing along with his heartbeat and breathing.
He didn't stop to think that something might have been wrong. Taking a seat on the side of the bath, he worked his fingers up and down the length of his cock. With every stroke, his cock and balls pulsed more and grew before his eyes. The strain of growth took him closer and closer to orgasm. Had he not been trapped in orgasmic bliss, he would have noticed that his legs and torso were getting more muscular under his already tight t-shirt and jeans. He would have also noticed a slight tugging at the end of his spine as something protruded into the back of his jeans.
He huffed and moaned as his cock, now clearly longer than a foot and staring to change to a mottled color, continued to pulse and writhe under his larger hands. A small light covering of black hair started to crawl its way up Josh's body, radiating outwards from his groin. He moved, adjusting his sitting position, and as he did so, he heard a large ripping sound coming from his jeans and t-shirt, both of which were now skin tight. But all Josh could focus on was the pulsing cock in front of him. He could feel his balls swelling with seed as he continued to rub his ever pulsing cock. He could hardly take it any more and started furiously rubbing his cock as fast as he can as his lower face pulled out into more of an equine shape. Without another thought, he jumped from his seated position as he felt a massive surge from the base of his cock and in doing so broke free from his remaining clothing. The contractions at the base of his cock were too much for him to take as his face contorted, grunting in orgasmic bliss. Thick, heavy, reaking streams of cum pulsed forth from his bulging cock, splattering the mirror opposite as the head of his cock flared, becoming even more horse-like.
After what seemed like an eternity, he fell down exhausted against the bath as he looked at his reflection in the cum stained mirror. 'What have I done?' he thought as he looked at the towering, muscular horse-like version of his body, which minutes before had been human. He lifted his cum-soaked right hand to his face to feel the horse-like muzzle and pointed ears as hus left hand explored the fine covering of black fur on his chest. As he started to explore his new body, his cock started twitching again from its now flacid position, within his horse-like sheath.
All he could think about was Katie and what he could of sworn was a tail...