You try to run away but the Black Stallions are faster than you, one of them eventually gets you and they press their fat horse dick into your Human anus, since you are a Virgin your tight asshole getting penetrated by such a thick shaft hurts, you try to get away but you are stuck to it, they spray some of their sperm into your butthole and you feel it burns and is sore, then you notice that your body is changing in all ways.
First your face stretches out into a long muzzle, like that into a horse, your nose and mouth are on the same part of the top of your face while your chin is on the bottom of it, you get long flappy ears and a black mane covering your head, your mane stretches all the way from your head to your back to your butt, then your human Arms and Legs turn into thin stubby horse legs and your Hands and Feet turn into Cloven Hooves, you also can't support your weight on your rear legs so you fall forward, then black fur grows all over your body and it at first itches but then it feels all natural, next comes another horrifying part, your penis, scrotum and balls rearrange themselves into something else, your balls go higher and become your ovaries, and they go to your Fallopian tubes and then your Prostate, which is now your Uterus, your Penis and Scrotum Wither and they turn into a nubby Clitoris head, a Urethra, Labia Majora, Minora, and Vagina Respectively. they are just below your Anus, there is no doubt now, you are a girl now. Lastly you feel something coming out of your rear back just above your anus, it is at first a fleshy tail but then it gets covered in fine black Horse Hairs, It is no Doubt a Horse's Tail. You try to cry out but you let out a Horse's Sound.
Oh No! By Catching you the Stallion has turned you into a Black Female Horse, A Mare, now you can never turn back into a human or a boy, you also can't turn into a stallion either, and you cannot escape from this Bad Dreamlike World back to the Arcade in the Real World, you are stuck this way and here forever, This new world is shaping up to be a real Nightmare.
Game Over.