Professor Quirrell threw away his wand as though it had caught fire, lurched away from Harry, and blurred down into his Animagus form.

Harry pressed his hands over his eyes, waiting for the pain to fade.

We did it. Professor Quirrell has the Stone.

Harry exhaled slowly. Transfiguration was powerful enough already, and now they had the power to make it permanent.

You couldn't Transfigure specific people, of course, and nor could you Transfigure lost books, but bizarrely enough you didn't need perfect knowledge of what you were making to Transfigure it - Professor McGonagall didn't have an encyclopaedic knowledge of porcine biology, and Harry didn't know the precise specifics of a rocket. In fact, even steel was complicated: there were different sorts of steel with different amounts of carbon and other additives. Transfiguration could clearly get information from somewhere that wasn't the caster's brain.

Harry opened his eyes and saw for the first time his surroundings.

The floor was worn and grey with dust, stained oddly brown in places. A slashed painting hung crookedly above a ruined fireplace, cold ashes spilling out over the floor. Nearby was a chair with three legs torn off. The room looked like it had been shredded. The whole place felt uneasy, like the quiet aftermath of a storm.

Harry suppressed a shiver. Ahem, said Hufflepuff, it might actually be a good idea to be afraid of magical haunted houses.

The snake lay unconscious on the dusty floor, a sealed silver pouch behind it. Harry couldn't Innervate Professor Quirrell, and he wasn't sure that it was possible to shake a snake awake. Absently, Harry wondered how the rules for Animagus transformations worked - if you touched the Stone to an Animagus, were they trapped forever? What happened if you turned into an Animagus while holding an indestructible magical artefact, then died?

It was probably a good idea to start planning the best applications of the Stone, so Harry closed his eyes and thought.

Transfiguration seemed even more strange the more that Harry considered it. The universe, or the Source of Magic, or whatever, would obligingly fill in all the necessary information about nerve configurations and biochemistry and such if you said give me a working pig from scratch, but not if you said give me a working Hermione Granger from scratch. It would give you all the information you needed, and which you absolutely didn't already know, to Transfigure a computer, but not to Transfigure a nanofactory. That didn't necessarily mean that nanofactories were impossible - Harry had tried to Transfigure a computer slightly more powerful than modern-day technology, and it hadn't worked either.

Harry had been slightly disturbed by the idea that a fully living pig had popped into being, then vanished. He had wondered what would happen if you tried to Transfigure a generic human like McGonagall had Transfigured a generic pig, but had dismissed the experiment as hideously unethical.

That pig had known how to stand up, so its brain had worked perfectly well. Could it have just been some sort of Platonic ideal pig? Probably not, since it would be perfectly possible to Transfigure, say, a pig with five legs... Had Harry been too dismissive of the idea that souls existed? The existence of Voldemort's Horcruxes was at least weak evidence for them, and it would at least explain why you couldn't Transfigure specific people.

You couldn't Transfigure magical objects, but you could Transfigure something magical into something mundane, so the Stone should cure things like lycanthropy. If magic was based on a marker gene, that probably wouldn't make the wizard into a Muggle.

That was when Harry made the obvious connection.

Wizards were essentially Muggles with magic. They counted as magical creatures, but that was only a genetic thing. It would be entirely theoretically possible to use gene therapy to make a Muggle magical.

You couldn't Transfigure the mundane into the arcane. You could Transfigure all of a Muggle's genes into the exact same boring old chemical DNA, but with the genetic marker for magic - the Blood of Atlantis.

That would at a stroke extend people's lives massively, make them much, much safer... There were bound to be problems, but the number of lives saved would be enormous.

There was no reason the Universe couldn't contain "I-win" buttons like the Philosopher's Stone.

Harry began to grin as the enormity of what had just happened hit him. He'd need to talk it over with Professor Quirrell, but things were looking good for world optimisation.

Harry opened his eyes and looked up.

He was looking at the tip of an outstretched wand.

The wand fell away. "Harry