Standing naked in the bathroom stall, your body continues to change. You feel your rear continue to expand as you begin to lose balance. Only by leaning against the bathroom wall are you able to keep standing. A bony protrusion feels like it is pulling itself from your skin. Soon, you are standing on four legs, having to move forward less you crush yourself against the wall by the toilet.
Meanwhile, through all of this, the change continued to move up wards. Course black hair sprouts from your chest and arms as your skin thickens. It continues up your back and face. Soon you are covered fully in black horsehair. Your horse penis continues to thicken, but you are unable to pay it any notice as your attention becomes fixated on the rest of the changes taking place.
Your muscles painfully expand, making you feel like you are being ripped in half from either side. Biceps bulge and expand to nearly twenty inches around. Groaning, you feel your chest inflate as well. Eyes closed as you try and manage the pain, you feel your entire upper body expand.
Finally, you feel your ears begin to grow long and pointed against your head as your nose and mouth push out and your eyes move to the sides. The bones rearrange as your head takes the form of a horse.
Times passes and the transformation completes itself. Many minutes pass before you muster the energy to open your eyes and stand up straight. You feel your head brush against the ceiling. Obviously, you are much, much taller than you had been. Nearly nine feet tall, all said and done. You are so wide across that you are practically stuffed into the stall. Awkwardly, you duck out of the stall, squeezing your equine body into the alcove. It takes several minutes before you are able to even appropriately maneuver yourself out.
You are only able to see yourself in a profile. You are massively muscled and covered in dark black fur with a horse like head. You possess the lower body of a horse. Looking around, the world seems so small to you now. Being nine feet tall and several thousand pounds of centaur is a big change from your previous state. What if you continue to grow as you get older and mature? You could be truly huge. Or are you already fully matured?
You feel aroused thinking about how large you are now compared to everyone else, but you are unable to reach your new equipment.
Obviously, you can't stay in here forever. You have to leave, into the newly shrunken world. But what will a centaur with a horse's head do on the outside? Opening the door, you decide you'll have to find out.