Amidst all the vials with labels depicting animals, fantastical creatures, or other natural curiousities, one competely different from the rest caught Mary's attention. Instead of some beast, the label simply showed what looked like a set of circuits. It reminded her of those circuit-themed logos every tech company in the 90s and early 2000s had, if a bit less corny. The liquid within it was equally unique, a black ichor that occasionally seemed to fizzle with some crackle of light blue. It was mesmerizing just to look at, and Mary couldn't help but ignore the rest of the vials in favor of this one little thing.
"Well... might as well go for the unique one, she mused aloud as she uncorked the vial. A quick sniff of the contents had a strange sort of burning sensation meeting her nose, like metal that was smoking hot - yet without any harshness or unpleasantness. In fact, she kind of liked it, lingering in the scent and smiling slightly before she bent back her head, throwing the whole thing down in one gulp. All the way down she could feel tiny tingles along her throat, like little stack shocks that continued until it reached her stomach.
As soon as she'd closed the vial back up and set it inside the crate, she began to feel an odd sensation in her eyes. A sort of... not pain. It didn't hurt, no, but there was... pressure. A bit of discomfort that had her squinting as it grew. With heat came pressure, and both feelings began to spread through the rest of her head. She had to lean against the kitchen counter, and for a minute wondered if she'd made a catastrophic mistake. It wasn't even painful, but... god, it felt like something was crushing her brain and her eyes.
And then, blackness. A complete lack of sensations.
When feeling came back, her eyes shot open, and she found quite a few new things dancing in her vision. Everything suddenly seemed so crisp, so clear - she focused in on the counter, and suddenly found her vision zooming in to a microscopic level. With a gasp her vision zoomed back out, as little bits and lines of data flew across her sight. Information about everything she was looking at, its size, mass, composition, anything she could possibly need. With confusion she ran to the bathroom, and in the mirror she could see what had changed.
Where once had been Mary's rather plain dark eyes, a set of icy blue irises set on otherwise entirely black orbs looked back at her. Leaning in closer, she could see tiny imprints on the surface, gemometric shapes shifting and moving - circuits, she suddenly realized. Her eyes were entirely robotic, a fact she found herself processing at lightning speed. In fact, she seemed to be understanding everything quite a bit faster now, almost as if...
She put a hand to her head, and could feel the heat of processors and CPUs running at high speed. Her brain... it was some kind of... computer? Mary flashed back to the circuits on the vial - of course! It was... some kind of machine formula. No, no, she quickly realized, not a formula at all. It was billions of tiny machines, nanites that she could now feel racing outward through her body - looking down at her hand, her eyes flashed to an x-ray mode, and she could see the swarm of them moving within her.
They didn't bring pain anywhere they moved - but she could feel their pressure and heat as they worked to replace her organic form at what seemed like an ardorous pace. It was, she quickly realized, occurring at lightning speed - it was her own perception of time that had changed, her computerized mind so quick that milliseconds seemed to drag on for an eternity. Every math problem she'd ever done flew through her mind, processed near-instantly, perfectly recalled from memories now stored in hyper-dense banks.
"Oh my god," she whispered, her tone an excited one. It should have terrified her, but... god, this was so incredible! The heat and pressure... it even felt kind of nice. Comforting, to realize how beneficial it truly was. The nanites, they weren't just changing her - they were improving her, and quite dramatically. Her guts, she could feel, had already been converted, forming a power system and cooling center to ensure her body was powered and didn't overheat. From there they had gone to work on her bones, replacing them with a fantastically strong metal alloy, able to support far, far more weight than any human skeleton could.
Her muscles were next to be worked on, the fibers replaced with something else that retained the general structure. Some sort of carbon composite material, much stronger than her old muscle, able to reinforce itself without needing to be torn and regrown. Where bones had once met in primitive joints, servos and motors took their place, providing an amazing range of movement with yet greater structual integrity than before.
The skin was the last part of her to be affected, as the nanites rose out to swarm across her whole epidermis. The entire layer above her synthetic muscle was quickly converted to a smooth polymer material, matching her old skin tone, yet clearly artificial. It was soft to the touch, even in spots along her joints where black lines separated various plates. She was quick to pull off her clothing, momentarily afraid that certain organs had been removed entirely; instead, Mary was delighted to see her womanhood and chest intact, now covered with the same smooth polymers. Despite her lack of nipples, a few quick squeezes confirmed that she still had soft, sensitive padding - and two fingers plunged into her fold affirmed that it still stimulated her just as much as before.
With a final swarming of her hair, converting the shown brown bob to a long, black mop of carbon-fiber strands, the changes were complete. She stared in complete and utter amazement, an artifical sigh passing her black polymer lips. In every sense she had become a machine, an android, one possessed of an utterly capitvating beauty. In her circuits she could feel the raw power, not just the electricty flowing, but her immense physical capabilities - and her new mind blazed faster than any other computer on earth.
She grinned, showing off her polished white artificial teeth. Mary couldn't even imagine going back to how she'd been before - this body blew any heap of flesh clean out of the water. The only thing that puzzled her cybernetic brain was what to do next - she desperately wanted to explore all the pleasures of her new form, but it seemed downright cruel to hog this gift to herself. The vial, after all, had refilled, and she could feel a cluster of nanites within her own body, ready to repeat the process. Those she cared about within her robotic heart surely deserved the same ecstacy she now experienced, didn't they?