It popped into his mind from out of nowhere. A visit to his grandparents farm and when he had run out in the morning and caught two of their horses locked in the throws of passion. The sight was one that stuck in his mind and was fateful to that moment when his muscles all seemed to tense at once and he fell to his knees.
"Tom? Are you all right?" Matt said, seeing his friend struggle. More worrisome was the rather bulbous look of Tom's ass. His hips and waist soon joined and the seams of his pants started to tug apart noticeably.
Thoughts of that same stallion that he found mounting that mare, crept into his mind and Tom clenched his teeth hard, feeling his cock stiffening at the thought.
"This can't be real," Tom said in a husky voice just as several loud pops from his hips had him wincing. "This can't be happening to me," he said just as he turned and looked back at what was happening behind him.
Another loud crack proceeded the rip of the bottom of Tom's pants wide open. With another grunt and a swell of muscle, bone and fat, Tom's ass grew more and his boxers went to tatters. Matt covered his mouth at the sight, which was more equine than human.
Below a nearly three inch, and growing, tail at the base of his spine, a puckered asshole, darkened from the skin around it, was showing. Worse still, as Tom wavered from a sudden onset of nausea, a slit opened up in the newly created space which just now was pulling in Tom's shriveled testicles. His cock, leaking of any male seed, pulled up just after, leaving a growing mare's cunt the only organ remaining.
"Uhhhh, ohhhhhh," Tom moaned, his toes curling but then merging, hardening and bursting through his socks to reveal the growing hooves he had. Eyes focusing again, those heavy looking things that clopped when he lifted and dropped them, sent his heart racing. "I couldn't stop thinking of my grandpa's stallion. I'm turning into him?" Tom asked Kate who was trying to hold back a laugh.
"Not exactly," she answered, hiding her mouth behind her hand.
As Tom was starting to process things, he felt a sharp pain in his bowels that settled into a warm feeling. His pants now shredding off, his lower half was looking decided equine and, as was starting to sink in, Tom realized he wasn't picturing the stallion now because that's what he was becoming, but because that's what he wanted.
"Oh no... no, not that," Tom whimpered, a burning sensation behind his nipples causing him to realize it was a mare's life for him.