You start to feel a tail growing between your legs and start to beg the old man to change you back. "Sorry kid, I have to wait about 20 minutes before I change you back. Unless you want some severe deformities."
The old man starts to walk away saying "Tell me when you're ready to turn back. You try to chase after him but trip and fall to the floor. It's getting harder to walk. You notice green scales starting to appear all over your body. Your tail is getting to big for your pants so you take them off. Your legs and arms start to shrink.
Most of your focus is on your tail as you sit there, alone, mesmerized by it. Your face starts to feel weird as it elongates. Your tail stops growing at 3 feet long. The green scales have covered your whole body. You tske off your shirt. Your arms and legs have gotten really short as they become webbed. All of your hair has fallen on the ground.
The transformation is starting to wrap up as you twist yourself onto your belly. Your elongated mouth stops growing and takes up a lot if your veiw.
The transformation is over as you have become an alligator. You can still think normally but you can't speak. You become weirdly aroused by the events that just took place as your dick comes out of a slit in your crotch.