You turn to leave but you are overcome by a tremendous pain. Looking down at your body you can already tell that the hair is starting to thicken. Your eyes burn as you feel your teeth press against your lips. Your fingers become bloody as the fingernails begin to fall off and claws burst through the skin. Your muscle begin to grow as what little fat you had disappears. You feel your tail burst from the base of your spine as you do all you can to suppress a scream. Your ears move to the top of your head as your feet take on a digitigrade stance. You let out a scream as your mouth and nose extend into a long thick muzzle. The last of your light gray and black fur comes in. Your teeth finish shifting around in your mouth and you open your eyes.
The color is a little distorted at first but as you get used to that form it gets increasingly easy. You're now around 9' tall and your clothes have changed to match your new form. You feel invigorated with power and you no longer care about your human form. There's only one thing missing and you need to get it.
You jump out the window in the next room run across the fields and through the woods.