Katie felt herself growing. Her teenage body grew to that of a beautiful twenty year old. Her large breast grew larger reaching the size of DD's. Her horse body grew with her to a full grown Arabian's body. Suddenly The feeling spread to her hands. She look to see her fingernails become a bitch black color and thicken. As she watched her pointer and middle fingers fused together, same for her ring fingers and her pinkie. The nails grew larger almost like hooves but the could still use her now three fingers.
Her body gained more girth to match her large horse body. She grew taller the she was earlier. Next was the top of her head. Her ears, which had relocated themselves there, became pointed, and were covered in fur the same color as her hair. Her hair grew longer. Finally, Katie's hair formed a mane between her ears, and it ran down her neck and back.
The fur covered her entire body. But with all this her body still resembled that of a sexy seductive woman. Her breast had grown a little more. The fur that had covered them were lighter than the rest of her body. The tingle then spread to her face, now even more changed, greatly resembled that of a true horse. Her whole jaw was pushed out into a muzzle, and her teeth had become large and flat. It was then that the fur raced across her face, and that the rest of her head completed it's reshaping.
As soon as her changes stopped she realized she had gained more weight from her friend in her belly. She felt as if her friend was growing fast within herself when she was consumed by convulsions of labor.