Mike stepped into the shower, and was immediately aroused even further as the warm water stimulated his cock. Mike couldn't help but grab his rod with both hands and give it a few more jerks. The water was also helping slick up Mike's member, to his delight.
Mike shook off his latest wave of arousal, determined to keep his new-found energy for Rachel later on. He grabbed his shampoo from the shower rack, and started washing his hair. He turned himself around in an attempt to keep the water off of his erect penis. Through the lather of the shampoo, Mike didn't notice his fingers starting to thicken and grow together. He was, however, noticing that the water seemed to be sticking to his body moreso than usual, but he just reasoned that it was some hard water.
As he rinsed his hair off, Mike began to smell a musky odor. "Man, I must really need a shower if I smell like this," he said. He shook his head to get some of the excess water out of his hair, and suddenly felt the strange sensation of his wet hair brushing his shoulders. "What the..?" Mike said in surprise. He reached behind and confirmed that his hair had amazingly grown down past his shoulders. His surprise began turning into confusion when his long hair then brushed his ear, and his ear involuntarily responded by flicking. Mike's hands immediately went to his ears and and he felt his almost completely formed horse ears.
"This can't be happening!" Mike said to himself. Mike reached for the door to the shower, but caught sight of his hand and stopped cold. He held his hands in front of him, and stared in growing alarm. His fingers had fused together leaving Mike with two thick fingers and a thumb on each hand, the tip of each finger almost completely black. Mike stumbled out of the shower and promptly fell to the floor. Mike turned his head to look down his body and gazed at perfectly formed equine hooves where his feet should have been.
It took awhile before Mike was able to get balanced on his ungulagrade legs. As he still wobbled on his hooves, he looked into the mirror to see that his face had now transformed to that of a horse as well. Mike couldn't believe the reflection that stared back at him. He was an ebony-furred anthro horse! Something else still caught his attention in the mirror though. Mike's penis had remained erect through his whole traumatic transformation. His member still rivaled a horse's in size, of course now it was exactly like a horse's cock. Mike looked down at his penis and could feel all his arousal slipping away. In response, his member started to deflate, and after a moment, was swinging limp. The swinging of his dick, however, brought all of Mike's arousal rushing back, and his member sprang back up to attention. Mike soon found himself masturbating the way an equine would. As he reached climax, Mike passed out from the pleasure.