The contents of this and the last chapter were originally intended to take place over multiple chapters but were condensed in order to push the story forward. Apologies. This is why I will never WIP-post again. :/

The growths inside Harry's skull have been part of the plan for this story since the beginning and it's a relief to finally get here. I loved all the different ideas people had about what they were and a couple of them were absolutely brilliant.

Pandora

"-is not a theoretical argument. We are witnessing it. So long as the Na'vi cling to the hunter-gatherer style of society, they will not progress."

His neck hurt. His everything hurt.

"Not this again. Linear sociocultural evolutionism is bullshit. Our personal past is not a template for progression, it's just our past."

"A past which demonstrated the trialling and discarding of different social, cultural and economic systems in search of the most stable and efficient. Without progression, we wouldn't have developed agriculture. Stored food for bad winters. Recorded our knowledge. We only gained the ability to turn our attentions to experimentation and invention, because we didn't have to search for and subdue our food every day of the week."

"Which ended in, oh, what was it? Oh that's right, a massively-polluted planet with historic levels of poverty, disease and suicide, run by mega-corporations. Which one of us is the evolutionary success again?"

"There's no need to be facetious."

"Said the sociological bigot."

Harry cracked his eyes open with a groan. Immediately, both arguing women came over to peer down at him. Doctor Li and Doctor Moa.

Oh, right. They also had human medical doctorates. Or, training, or something.

"Hey, easy there, Harry." Moa soothed. "Just take a minute. Breathe. Relax. You're safe."

"What's your level of pain, from one to ten?" Li said immediately afterward. Dr Moa shot her a stink-eye.

It took him a moment to understand what he was being asked.

His head and neck throbbed again. His eyes felt like they were literally bruised and his back teeth hurt. His ears hurt. But.

"Three." He muttered, licking his lips a little as he realised how dry they were. How long had he been out?

They didn't have proper medical equipment at their slapped-together module base. Some sort of future-basic x-ray machine had been jury-rigged together but the second it showed shadows in his brain where shadows shouldn't be, they'd put a call into Hell's Gate.

Their doors had opened immediately, but only for Harry, the two Doctors and Mike.

Some of the tests they wanted to do took a long time, so they'd knocked him out while running them.

"That's not so bad." Moa said, though the tightness around her eyes suggested otherwise. "We've got you on some pain meds right now. Let us know if it gets worse and we can see what else we can scrounge up, okay?"

"What's wrong with me?" Harry asked bluntly.

Dr Moa glanced at Dr Li.

"We don't know." Li said brusquely. "All the new tests told us was that whatever is happening… it's affecting your skull as well as your brain. We've tested what we can and performed a small biopsy-"

"What?"

"-to determine if it was parasitical or bacterial in nature, but results are… inconclusive."

"I didn't give consent for any biopsy." Harry snapped, a heavy hand coming up to feel over his head. There was a small shaved section, nestled in which was the smooth feel of medical sealant.

"You didn't need to." Li dismissed him. "As the senior medical and scientific officer, the RDA delegated their authority to me."

Harry went cold, then hot. He bit back the temper licking at his insides - by the time he got back to Earth, they wouldn't have any legal sway over him. He forced himself upright. Moa adjusted the bed but kept a sharp eye on whatever biometrics were being displayed.

"In this, I do not recognise their authority." He said, as steadily as he could. "A Wizard becomes of age when they're 17. I've played along with the RDA's so-called guardianship of me so as not to make waves but when it comes to my medical care, you will obtain my permission first. Or you will not like what happens."

Dr Li's dark eyes flashed with her own temper, her lip curling slightly before she looked away and picked up a tablet. By the time she turned back, her face was smooth again.

"This is the inside of your skull." She said flatly. Harry's eyes dropped to look at it. A 3-d coloured image of his brain was slowly rotating, with a slightly fainter coloured outline of his skull around it. A flick of smooth fingers later and the electrical activity overlay was removed, showing just the physical form.

Two small lumps were plainly visible, on the left and right side of his brain. He glanced to the right, where the same image was displayed from a different angle, showing his skull directly over those lumps. It was coloured a very slightly different shade.

"The bone seems to be softening. Or, was previously softened." Moa explained carefully. "It's why we thought this might be a previously un-encountered parasite. I asked some of the traitors to check in with the Na'vi, in case they've seen it before."

"Traitors?" He asked, vaguely surprised behind the flat horror he was working damned hard to suppress. Moa shrugged.

"It's what everyone calls them. Anyway, word is apparently 'no' but they do also have a stronger skeletal structure than us so we can't actually be sure just yet."

"Regardless." Li looked close to rolling her eyes. "We've obtained permission for temporary accomodation, until we know what this is. We're reasonably confident that it isn't a parasite, or at least not the kind that lays eggs-"

Harry stared at her.

"-but regular checks in a properly-outfitted facility is obviously critical. Doctor Moa and myself will also begin testing the samples we took, to see what else they can tell us. If this is bacterial, we will of course do our best to work up some some sort of treatment."

He blinked, and lowered his eyes.

"Thank you."

"Unnecessary. With the disruption in planned staff, I am currently the senior officer responsible for the wellbeing of all authorised humans on Pandora." Li dismissed.

"Well, thanks anyway." He said again, partially to annoy her, before turning to Moa as Li left the room.

"Am I in danger?" He asked her frankly. Moa looked like she was calculating a soft-serve response for a minute, before sighing and being just as frank.

"When the brain is involved? There's always danger. Hell, every time us Avatar-drivers get into a link pod, there's technically a chance of malfunction leading to irreversible brain damage. But, so far, the increased pressure is within allowable parameters and there doesn't appear to be any damage done to your brain yet."

"Yet." Harry confirmed. Moa shrugged.

"Yet." She agreed. "But, we're watching. Okay? If we see it starting to progress in a way that is dangerous? We'll go on in to remove it."

"Not without my permission you won't."

"We won't be able to get permission if you're unconscious on the ground 'cause your brain is bleeding." Moa shot back. "Now. If you're feeling up to it… I need to ask you some questions."

Harry leaned back with a sigh. "Yeah, go on then."

Dr Moa walked him through some standard questions testing his memory. Who he was, his age, where he was, where he was born - that sort of thing. Some he couldn't answer - like what he had for breakfast a few days ago. Then came questions about his mood. How he was feeling now. How had he felt before? Had he noticed any unusual mood swings since arriving on Pandora? What about before then? And finally, how did his magic feel now compared to before?

"Full," He answered "but now that you mention it. I don't feel… surrounded anymore."

Moa nodded as she checked another answer off and made notes.

"We thought that might be the case. You re-located into the mountain to try and get some space from it all, right? Well, Hell's Gate may not be a mountain but it is actively shielded. And it's been here for years."

And humans have lived here for years, Harry thought but didn't share. It was just a whisper of an instinct that said that factor mattered too.

"It's a relief." He admitted. "Not quite worth the price of admission, but I suppose I'll take my silver linings where I find them."

"Goooood attitude." Moa grinned a little. "Okay. Are you hungry? Good. I'll bring you something to eat and then it's probably best if you just take a nap. I'll scrounge up some kind of entertainment for you a little later - we didn't bring anything but the absolute basics from base, sorry."

Harry nodded and waved with his IV-embedded (how had that not improved in over a hundred years?) hand as Dr Moa left as well.

Alone, it was harder to hold back the fear.

What was happening to him?

Pandora

He fell asleep before Dr Moa got back but woke up when she returned to switch out his pain medication. With her were two strangers and on their heels was a Mike who looked like he hadn't slept in a couple of days.

"Hi, Harry, right?" The skinnier of the two strangers smiled at him. It was a little stiff, but only in that awkward way that adults could be with teens. He reached out a hand to shake Harry's. "I'm Norm. Norm Spellman. Which… I'm just realising is kind of kind of weird, considering."

Spellman, meeting a Wizard.

"Well, a good kind of weird, I hope." Harry smiled uncomfortably back, shaking his hand. Knowing how uncommon hand-shaking was in this time, he was a little impressed that some random guy who'd been on Pandora for who-knew-how-long had somehow already picked up that it was the 'appropriate' way to greet him. Maybe Mike told him? Nah, Mike wouldn't tell anyone anything about him, too paranoid about it being used again him. Maybe Norm was just from a background that still did it.

Besides, his words implied he knew about his magic, so…

"Did you leave Earth just recently?" he asked.

"Well, relatively speaking, yeah." Spellman followed his train of thought with ease. "I was with the last group out before, uh, everything went down. Oh! This is Max. Max Patel. He's been out here a lot longer."

"Thanks, Norm. Just call me Gramps while you're at it." Patel - Doctor Patel? He was wearing a labcoat - grumbled, as he stepped forward to shake Harry's hand as well.

"Nice to meet you both." Harry greeted automatically, pain still radiating throughout his skull and down his neck.

"Likewise." Patel grunted, eyeing him as Spellman nodded and smiled. "So you're the magic kid, huh? Who does real magic because you're King Arthur reborn?"

Norm grimaced a little at the nearly-hostile lack of belief that was very plain in his colleague's words.

Harry wordlessly conjured a black, silken top hat, then reached into said hat and conjured a tiny white rabbit. He pulled it out and handed it to Patel, who nearly physically recoiled as his fingertips registered soft fur and the tiny warm beat of a living heart.

Harry snapped his fingers, finite-ing it all. Patel and Spellman both stared at him, boggle-eyed.

"Pretty much." He agreed. "Except the reborn thing. So far as I know. Hello, I'm Harry. And no, you can't do tests on my magic, I've signed a contract already."

Pandora

Over the next few days, Harry mostly only saw Dr Moa or (it turned out) Dr Spellman. The latter was quick to offer to just call him 'Norm', which Harry found easier than with most of the doctors he knew. Part of it was habit from his professional engagements on Earth but most of it was Norm himself. He just seemed more relaxed than all the other scientists/researchers he'd met. Or maybe just less intimidating, since he wasn't 'on the clock' anymore. Probably never would be again, if the RDA got their way. Norm wasn't a medical doctor either, he was an anthropologist - which Harry was very familiar with. The man was just as eager to talk with him about his time and his culture as all the rest.

And it served as a pretty decent distraction from the pain that never really went away.

Dr Li on the other hand had gone back to base, despite the fact that everyone knew she thought that Hells Gate was a much safer place to be. Apparently an argument about certain recent events had escalated into a hair-pulling screaming match with another scientist that got so loud, Harry had heard it all the way in his medical isolation room.

Over the sound of the snap playing on his tablet.

She'd been escorted out and told not to come back. Moa was still sending her updates, but the base wasn't letting anyone else come to replace her. A few of the idle scientists from the original inhabitants had volunteered to help Dr Moa if they could but preciously few of them happened to specialise in the right sort of biology - or disease, which was still an option on the table.

Meanwhile, Harry watched movies with the brightness and sound turned down when he could, tried to nap through the pain and increasing light-sensitivity when he couldn't and just generally had a miserable time of things despite Mike, Norm and Dr Moa's best efforts.

The pain medication in his auto-dispenser started to increase, but it didn't feel like it made a difference.

They took blood, more biopsies and regular scans - but couldn't work out what was happening.

"There's no immune response." Moa explained one night, too tired to hide her baffled frustration from him. "There's localised swelling and inflammation but no increase in white blood count, no swollen lymphatic glands, fever so mild as to be almost non-existent, nothing! If it weren't for the scans, I'd say you just got knocked in the head."

"It's growing, though." Harry croaked out. He'd started puking shortly after breakfast today. He'd been given anti-nausea medication, but only after even more testing that concluded the vomiting to be a bodily stress response. Turns out, the body was quick to vomit any time anything odd happened, just in case it was because the idiot in charge had eaten something they shouldn't have.

"It is." Moa agreed grimly. The shadow was wider and, they hadn't realised until too late, had been growing within the folds of his brain, not just on top. They could go in to scrape it away but the 'roots' would remain a problem. They'd possibly grow right back.

"It's not a parasite. We're almost certain." Dr Moa continued. Harry closed his eyes as she began to pace. Anti-nausea medication could only do so much. "It doesn't seem to be fungal, bacterial, cancerous or any form of alien plantae. The Na'vi don't recognise it at all, though their bones are much harder than ours so maybe… I'd almost say it was neoplasmic, except that doesn't really match either. Whatever is growing, it's not tissue. It's more like…"

She trailed off, maybe realising that his literal sick bed was not the place to get into a rant.

"Sorry, Harry." Softer now, she stepped closer and smoothed his hair back. It was unwanted but he didn't care. He didn't have the energy to.

"We're going to figure this out." She promised. "Just hang in there."

Pandora

Days, what he would later find out were actually weeks, passed.

Until one day, he woke up feeling fine.

Stiff, achy and still a bit of a headache, but… otherwise fine.

Except that there were… lumps. On his head. Two of them.

Pandora

"Okay!" Moa snapped on some gloves. Presumably, they were tougher than the spray-on kind. Why she'd need them was somewhat worrisome.

"These seem to be benign." She explained, while Mike held up the closest wall and Harry kept his eyes on the feed of what she was doing.

"Seem to?"

"Mmm. You remember how your skull was softening? Well, that kept happening. Whatever was growing on the inside, started to work its way through. We kept an eye on it and we spoke to you a few times about it-" Harry remembered no such conversation. "-but besides the pain, your body still wasn't really reacting. It still didn't view this growth as an invader. And Dr Patel had a theory that seems to be proving true."

"Which is?"

Dr Moa carefully parted his hair and gently palpated the swollen lumps. They were barely bigger than his thumb and felt hyper-sensitive. He clenched his fists in his lap to stop himself from slapping her hands away.

"The growth? It's not normal tissue. It's nervous tissue. The kind that normally connects your brain with the rest of your body to carry signals forward and back."

"What the hell?" Mike asked what Harry was thinking.

"Right?" Moa exclaimed, clearly having a different conversation. "It's an utterly bizarre location for it to develop at all. We compared it to the Na'vi tswin growth, since that's what Dr Patel is most familiar with, but the similarities are very few. Both Avatar and Na'vi tswins grow directly from the midbrain - which is located in different places depending on the species. If this were to be anything like it, it would have to grow in the same place as in an Avatar body. Right? But it's not."

She leaned back and removed her gloves in such a way that she only ever touched their interiors.

"So, is it dangerous?" Mike demanded, an oft-repeated question. Moa shook her head, but shrugged.

"We don't think so. The pressure on the brain caused by its initial growth - and by what we now realise was its attempt to grow up and through the skull - has dropped right off. We'll keep an eye on it, but for now we're back to wait-and-see."

"Oh? Not going to follow Dr Li's directive?" Mike needled.

Harry's eyes snapped up. Moa shrugged at him.

"As soon as Dr Patel made his initial identification, Dr Li sent the order through for it to be surgically removed. Your bodyguard here 'reminded' us all that you didn't consider her to have medical authority. Drs Patel and Spellman 'reminded' me that they weren't about to allow the RDA - or their representatives - to boss them around so I reminded Dr Li that pissing off a guy who could pull together an exploded shuttle mid-plummet probably wasn't the best idea."

She sighed. "I just know I've got a write-up in my future."

"Thanks." Harry offered, genuinely grateful. "If she'd pushed it… I don't know what I would have done, really. There are laws about using magic against Muggles in self-defence but vengeance is normally crossing the line. Also, how would Muggle laws even view it if I shrank her down and put her in a bottle on the shelf?"

"Last time I checked, our laws don't cover magic use." Mike offered.

"Last time I checked, that was six years ago."

"Point."

"Well, a person has to be human before anything really punitive happens." Moa maybe-joked. "I went to med school with her and from day one, I was sure she was a robot. Some of the things she used to say, you wouldn't believe."

"Is that possible?" Harry asked, stretching gingerly and sliding off the bed to his feet under two sets of sharp eyes. They had robot secretaries, robot sex workers and robot assassins/bodyguards. Robot doctors didn't seem so unlikely.

Moa hummed and hovered at his elbow as he stiffly forced his body to move, walking carefully across the room to another bed. By the time he got there, he was ready to crawl in and go back to sleep.

"I was sure it was. I may have gotten a little obsessed. A little. Long story short, I almost failed my finals, I confirmed she bleeds red and she never found out it was me so, lets never mention it again."

Pandora

"Sssssst. Argh." Harry scratched vigorously at his scalp, working up the pleasure-pain sensation that soothed the itch. He couldn't believe how maddening it was - he knew he shouldn't scratch, he'd once seen Dudley scratch his leg raw and bleeding, but it. was. so. itchy!

"Hey, hey, easy!" Someone - Norman from the sound of it - grabbed his hands, pulling them away. "What, did you bring some lice from Earth with you? Actually, please tell me you didn't. I'd never be able to show my face again if we managed to introduce those disgusting things to Pandora."

"No." Harry muttered unhappily. "It just itches."

"Well, don't scratch." Norm scolded, although his hands were gentle as he carded through Harry's hair - presumably looking for signs of infestation. "It'll only make it itch worse. I'll get you something to spray on, it should numb it long enough to heal. Check your nails, because you've torn your scalp up pretty bad."

Glumly, Harry glanced at his nails. Sure enough, small amounts of blood caked them. He hadn't felt anything but the satisfaction of really getting the spot. Even though his scalp now ached, it was still itchy.

"Just hang on." Norm released him. "I'll go get that spray now, before you scratch yourself bald."

Harry watched him go and furiously held back from further scratching. It was much, much harder than it should have been.

...Maybe he could just sneak in a little one...

Ahhh, that felt better. Or, it did until-

"Ow-shit!" He snatched his right hand back. The edge of his nail must have dug right into an exposed nerve or something because that hurt. And worse, it still felt itchy! His fingers twitched to scratch even as remembered pain made him flinch.

Then Norm was back and he gratefully let the man spray a load of chemicals at him which, although not quite stopping the itch, did at least deaden it a bit so Harry could ignore it.

"Thanks." He offered, accepting the spray bottle.

"No problem." Norm smiled. On his way out, he couldn't seem to stop his hand from reaching up to scratch at this own scalp.

Liberal use of the spray over the next few days kept him from scratching too much but the strange, prickling sensitivity that remained wasn't much better.

The ongoing scans showed increasing thickness of whatever was growing (if he sprouted hairy pink worms like what the Avatars had, so help him Merlin-) but the swelling seemed to max out at about the size of large golf balls. Some of his stretched-skin hair started falling out. The lumps themselves got looser, like maybe they were starting to shrink again? Or there was a lump (cyst, Moa called it) inside the skin that wasn't anchored to the skin.

"Squish, squish, squish, squish-"

Norm paused the next time he entered the room. Harry, long past mandatory bed-rest, was sprawled on the floor in the manner of an utterly bored youth. Two index fingers were raised and idly poking the swollen cysts on his skull back and forth.

He stepped back out of the room and kept walking.

Pandora

He ran out of spray.

The next time Dr Moa came to visit, Mike being off at lunch or taking a nap or whatever he did now that he was satisfied that Harry's general area was safe, it was to find him scratching madly.

"Quit that." Moa scolded. "Do you know how dirty our hands get? When's the last time you washed them? If your answer isn't 'five seconds ago and I haven't touched anything else in this room since', you shouldn't be scratching."

She glanced over his biometric display with the ease of habit and picked up his tablet to check his history since the last check-in-

-just as Harry's nail broke through one of the swollen sacs with a twinge of pain and a gush of fluid. He yelped, more grossed out than hurt as his hair was plastered to his head and something weird-smelling started dripping down his face. Dr Moa's head snapped up. She stared.

"What? What is it?" Harry demanded. "I popped it - what?"

She fumbled for one of the spray-on-glove dispensers, then reached up to his head. Harry leaned warily back, feeling the air brush against the fresh wound. It didn't hurt, it just felt very cool. As in, cold.

Moa's fingers gently brushed over the flap of broken scalp then, as he continued to show no signs of pain or resistance, gently tugged and nudged until…

Something sprang free.

"WHAT?!" Harry's whole body jolted. "What-what the bloody hell was that?! What did you do?"

A slightly-glistening gloved hand reached back to pick up the dropped tablet. With a couple of quick presses, It began to display a video feed of whatever was in front of it - ie, Harry and Moa.

"See for yourself." Moa said, uneasy and a little nauseated and absolutely fascinated as she handed it to him. "Just… don't freak out, okay? I don't… think it's bad."

Hands shaking, Harry held the pad up, angling it like a mirror to see the lumps just up and back from his hairline. Except there was only one lump. The other, burst and with flaps of skin lying flat on his hair, had been replaced with… with…

The closest thing he could relate it to was the curled frond of a fern. There was a slim 'stem' of red skin, smooth and wet, growing out of his head like one of the aliens in Dudley's computer games. It bent backwards slightly, towards the back of his head, bowed under or curled around the weight of something that… he turned his head… something that looked like a marble made of flesh, squashed semi-flat into an oval shape, hanging at the end.

His eyes flicked to the other swollen lump, knowing there'd be a mirroring growth inside it. Movement drew his attention back to the first and he watched as Moa (who had stripped and re-applied her gloves) gently moved his hair aside to look closer at the part where it merged with the rest of his body. The skin there was surprisingly not raw, there was no open wound at all. It was like normal, new skin. The kind found under a popped blister, maybe. It was sensitive, but even he could see black hairs already poking their way out a bit. Whatever the weird red things were, he at least wouldn't have golfball sized bald patches around them. Gentle fingers then touched the stem - which felt really, strangely invasive - and barely brushed the bulb at the top before Harry forcefully yanked away.

"Yeah. Don't. Don't touch that." He gasped, startled to find his heart kicking in his chest and his lungs heaving for air. There'd been something there, something dangerously close and invasive and he just wanted to tuck his stupid little growths away where nobody could see - or touch - them ever again. Moa held her hands up apologetically.

"I won't Harry, I promise. Let's just take some scans and go from there. Okay?"

Harry shrugged and nodded. The other lump was itching mightily and he felt only a little guilty that he'd probably go for it the second she was out of the room.

The woman hesitated for a long second - were his intentions painted on his face or something? - then patted his shoulder carefully.

"Just… don't do anything drastic, okay?" She pleaded. Harry stared at her blankly for a long second. He hardly thought popping what amounted to a giant blister was drastic. Moa didn't seem reassured but skedaddled out of the room anyway.

Oh. Oh, she probably meant 'don't cut it off or yank it out'. Yeah, well, there was no worries about that. Even the thought of someone else touching it had him breaking out in a cold sweat. The thought of yanking or cutting… yeesh. No. He might have to wear a hat for the rest of his life or buy a wig, but…

Then Moa was back, along with Mike and Norm and Dr Patel and half a dozen other scientists - some Harry had never seen before.

He sighed, just as the second swelling he'd been absently scratching at abruptly burst against the edge of his fingernail.

Whoops.

Pandora

There'll be a bit of a wait for the next chapter.

So, is this just the human version of a tswin? No, though it may seem similar. This is something that has a lot of roots in human history, though multiple cultures, over thousands of years. I had a lot of fun tying all those threads together.