A searing pain ripped down her spinal column and concentrated in her tailbone. Before anything else, Mary let out a scream of both surprise and torture. She heard the cracking of bones inside her rear end. It felt like the skin on her lower back was ripping itself apart. She continued to groan and gasp. Her nerves got the better of her and allowed her legs to buckle, dropping Mary to her hands and knees. She heard fabric tearing and knew it must be her skirt. She had a very good idea what was growing from her, but a panicked part of her mind dared not look. After several more seconds of the horrible pulling and cracking, she managed to steal a glance behind her.
Growing slowly from her back was a massive dragon tail. Its dark green scales were offset by blood-red spines that ran every six inches getting smaller near the tip. The tail was already a couple yards long, and growing steadily across the floor.
Twisting her back like she was had a bad effect on the growth. She felt another twinge of pain, this time heading upward to her neck, and Mary pulled her head back around to make it go away. Continued growth elicited more groaning, and tears started to wet the carpet as they streamed from her downturned face. After what felt like an hour--but was likely only a few minutes--the pain subsided. Mary panted, tears still gleaming on her cheeks. She pulled her back upright once more, then slowly turned her head back to face the inhuman appendage that had so painfully forced its way out.
The distinctly draconic tail was incredibly long. Mary guessed it had to be eight feet. It lay long and flat across the carpet, almost running into the wall. Where it merged with her human back, it was practically a foot thick and had torn her skirt and underwear clean off. She gently touched its skin and felt the cool, pebbly scales that glistened in the light from the nearby windows. She slid a finger up one of the closer, larger red spines. It stuck out of the scales like a thick, magnified hair or needle, and was very sharp at its tip.
What had she been thinking? Fantasizing about being a dragon might have been fun, but now that her eyes beheld such an enormous appendage attached to her very own body, she wanted nothing more than to be human again. The pain of the growth still fresh in her mind, Mary shakily stood on her legs and slowly made her way to the vial box. Her tail was incredibly heavy and seemingly unresponsive to her commands to move, at least for now. Once she was standing over the box, she began to search for a vial with a picture of a normal human being on its label.