The person grunts while grabbing their gut, looking as if they were in excruciating pain. Their eyes go bloodshot as you see them physically change. They curl up in the fetal position as they scream in pain, veins bulging all over. They even begin foaming at the mouth as they seem to be growing. Their muscles get tense and swell up, their hair gets longer and changes texture. You and your girlfriend back up from the screaming person, ready to make a break for it should they go on the attack. You are in awe of the next changes that overtake them.
Their face stretched out as they scream, their voice getting raspier with each scream. Their spine grows a nub as it extends, the popping and cracking of bones makes their changes visceral. Their ears slowly gravitate to the top of their head as they stretch out, gaining the ability to flap freely. Their tail nub gets longer and longer as hair like on top of their head covers it. Their skin darkens with a dark colored hide as their hands become massive and their feet start to shift into hooves, turning black where their toes were. If their was any questions about their gender, they were immediately silenced as a massive equine shaft rips through their clothing, followed by their swelling nuts. It was a massively muscular horse man, and from the looks of it, a massively horny horse man. He snorts as his massive cock spurts a little precum onto the ground.