One can not have shine without dark.
Spectra was paralyzed, and not just in fear. A stallion had come up to her and asked her to smell some flowers. He claimed they were for a special somepony, and that he didn't have a nose for picking the best scents.
The second she had inhaled, a powerful paralytic overwhelmed her body. He had then carried her into a nearby cave, just off the beaten path.
"Normally, my trade is more in blow-up dolls and the like," the stallion explained. "However, I have a client that absolutely needed a mint condition white earth pony, with two-tone hair. You fit the bill perfectly! I hear he just wants a toy for his little filly, and good news, that's you!"
The stallion set spectra down in the cave, and lifted up her right foreleg. "Such a beautiful mare, I'll get you into a lovely pose. You see, I can mould your body into a nice playful pose, like so." He turned her head to the side, tugging the corners of her mouth into a smile.
Spectra tried to scream, yet she was still fully paralyzed. She was getting just enough air to have not passed out yet. The stallion continued to touch every inch of her body, groping her, until he got her in the perfect position.
"Now, this is usually the least favorite part, I'd imagine. Never bothered to ask."
A large needle was pushed up to her belly button, piercing into it easily. The pain shot through her flesh, causing her to cry. Air seemed to blow through the needle, causing her to inflate from the inside out.
Heat spread through Spectra's body as hot air replaced her organs. It didn't hurt, on the contrary. She felt like she was melting into a delightfully hot bath. Her body was getting lighter, floating, relaxing oh so sensually.
"Haven't tried helium before, normally it's blow-up doll this, and blow-up doll that. I must say, however, I may sell party balloons on the side. I suppose you can't see your shapely flanks expanding, but trust me, it looks stunning."
Spectra could feel her skin stretching, bulging out from the inside. Her skin began to tingle and melt, fusing into thick latex. Both flanks expanded, becoming plump and round. The seams stretched, and there was a slight squeaking as she was over-inflated.
Her breasts expanded too, yet at the same time became more cartoon like to suit the needs of a filly's toy. Spectra's barrel was rounded out nicely now, and her front legs stretched wide to support the weight she no longer had.
Spectra's skin began to cool, changing from skin to smooth latex. Her head expanded slightly, and she felt the needle withdrawn.
"Well, now we just sit back and watch the last stage."
The cooling skin ran up her spine, a tingling sensation being that last feeling she'd have as a pony. Soon the rubber crept up over her chin, sealing her mouth into a permanent smile and turning her nostrils into small, painted on dots.
Her eyes became a slightly-harder plastic, and her vision adjusted to accomadate. Spectra couldn't move, and felt like she were watching a play at the theater, with her eyes the windows to the stage.
Spectra heard a howling as a wind picked up from places unknown inside the cave. It hit her in the plot, blowing her towards the cave mouth.
"Shit!" The stallion charged after his helium balloon. All it had taken was that one gentle tap to rocket her outside where the wind would carry her off.
Spectra floated out of the cave, now upside down and tumbling through the air. She saw the stallion shrinking in the distance, and an ocean of trees beneath her. Her entire body felt lighter than a feather, blown along by the breeze.
She imagined this must be what flying felt like. Perhaps she'd spend the rest of her life flying, or perhaps some other filly would find her and play with her. Spectra even considered a stray tree branch might pop her.
However, none of that mattered for now. She was flying through the clouds, high above Equestria, a giddy sense of anticipation growing.