Jeff watched as his face slowly started inflating, his teeth becoming a lot bigger until his mouth was nearly completely stretched, then the rest of his face followed, quickly stretching out and covering in fine brown hair until it had completely turned into a horse muzzle. Wheehat's hahahappening?", Jeff startled between whinnies. His ears had also become a lot pointier and movable, as the brown hair completely covered his body...
His chest muscled bulged up, his abdomen forming into a firm sixpack and he could witness a huge muscle structure beneath the brown fur, becoming about a foot longer when his legs stretched and gained a huge amount of muscle in his thighs. His toes blackened as they melted into his feet, rounding out into solid black hooves, making Jeff lose his balance for a moment and clipclopping across the floor for a moment before he managed to lean against a wall. He now witnessed a huge lump in his underwear that extended even beyond them, as a red tip poked out with black skin around it. His underwear already as bursting point due to his grossly expanded horse butt now finally got a hole torn in it when a long black bushy tail pushed through it, merrily flicking back and forth. To top it off, Jeff now had a full, raven black mane running down his back.
For a moment, he reacquainted himself with his new body, experimentally waving the tail back and forth and taking a few steps on his rear hooves, and even controlling his speech to cut out the whinny twitches. When he was ready to continue, he decided...