She laughed suddenly and then said, "Fine, prove it. Make a wish, wishboy."
I smiled and said, "I wish you were an anthro unicorn." Sara's face screwed up in shock and bewilderment. An anthro unicorn? Blood ran to her cheeks. Did he know her secret? She glanced back at her bed, piled with stuffed animals, but horses and unicorns dominating. She'd always had a fascination with the mythical beasts, what girl didn't. Unicorns were sleek, beautiful and of course, magical.
Sara's thoughts were disrupted by a tingling all over her body. It wasn't unpleasant, almost pleasurable in it's uniqueness and warmth. Sara groaned, lost in the sensations now jolting all over her. Her body was growing, filling her tie-dyed t-shirt and jeans. She twisted and stretched her back as the fabric pulled taut and started to creak from the building pressure.
One, two groans escaped Sara, and then a whimper. Her clothing was tight against her and pressing painfully against a frame three sizes too big for them. Sara bent over sharply, her t-shirt and bra ripping apart as a chest more rounded burst forth. That was one relief, but Sara's jeans held on against the onslaught of expanding thighs. Whimpering and whinnying, Sara grasped her legs, not noticing or caring she was topless in front of her cousin.
Sara felt her shins stretch and thin, but her upper leg swelled with muscle and flesh and strained against the fabric of her pants. It was a battle the pants couldn't win try valiantly as they might. Groaning and gasping, Sara flexed her legs straining the pants beyond what even they couldn't hold back. Sighing heavily, Sara brushed the remnants from her. She stepped back to look at herself for the first time with a clear mind. She'd grown taller and larger. Her legs had filled out on the top and were a good half-way to being those of a horse's. All over her was a coat of the most soft and shimmering white fur she'd ever seen. Running a hand over it sent shivers of pleasure.
But she wasn't done changing yet. Sara watched her hand and fingers shorted and darken on the tips, becoming hard hooves. Her fingers remained, thankfully. It was her face and head that next began it's change. Her neck thickened and arched just slightly even as a long man of silky smoothing hair shimmered it's way out and over her delicate back. Sara would later admit that the strangest part of her transformation was growing a muzzle. It was so different than her human face as it pushed outward just a couple of inches. Sara cracked her new longer jaw trying to get used to the strangeness of it. Next her ears stretched up and out, creeping up to the top of her head. Sara should her head, reveling in the feeling of her mane as it lightly softly over her shoulders and back.
There were two more pieces to come in and Sara was eagerly waiting for them. These were things she'd longed to feel and not just imagine. She glanced over at her stuffed unicorns on the bed and smiled. All of her daydreaming and wishing and imagining what it would be like to be a unicorn. All those times she'd wished for just something like this, and it was really happening. It was happening, wasn't it? This wasn't a dream? Well, either way, dream or not, it was the most vivid, and pleasurable, experience she'd ever had. The way her hands ran over the fur on her large and round hips, to how her ears twitched and rotated as they picked up new sounds. It was all so amazing. And it was all happening to her, Sara, the lover of unicorns.
Sara brought her mind back as she felt one of the things she had been longing for: her tail. The appendage snaked down behind her, sprouting silver colored hair and sparkled in a rainbow when the light hit it just right. The long ends tickled the back of her legs. Sara whinnied in delight.
Then last of all, the one thing that made a unicorn a unicorn: the horn. The sensation of pressure and hardness pushing out of her forehead brought Sara to touch the growing horn. It was pure white with a large twist to it. If you looked closely you could see a myriad of colors reflected back in a prismatic kaleidoscope that you could lose yourself in. The horn grew out a good foot and came to a dangerous looking point.
It was over, Sara had become an anthro unicorn. A beautiful, delicate unicorn that belied a strength and power underneath.
James had watched the entire thing and hadn't expected anything like the show he'd seen. He stared at his cousin, mouth open and lost for words. Sara, nude but covered in white fur, James had to admit, looked incredible with her unicorn hourglass shape.
"James," Sara stammered, "I...umm...thank you! You can't know what this means to me."
James shook his head to clear the cobwebs and tried to think clearly about what next he should do with his magic ring.