A/N: It seems my recent trend of almost, but not quite killing my main characters seems to be continuing... But fear not, they always survive, even if they're vastly changed!

Warnings: this fic has Harry almost-not-quite die by the hands of the Inferi. His genetic code is then mutated by a symbiote. There are some descriptions of his innards and them not being inside his body. Harry has a panic attack about being underwater, and believes he will drown - he doesn't.

"Sir?..."

"Sir!?"

"Are you okay?"

"Wait, of course you're not. I just forced a gallon of an unknown, probably toxic, potion down your throat. I'll get you some water, Professor Dumbledore." Without a thought to the potential consequences, Harry grabbed the goblet and dipped it into the moat surrounding the plinth that had held the locket.

The instant the lip of the cup hit the water's surface it began to boil, writhing with long deceased bodies as the Inferi began to rise to the surface. They surged up, skeletal fingers grasping at Harry's wrist and arm and swiftly pulled him into the water.

Sharp bone slashed two deep cuts into his abdomen, the pain and the feeling of warm blood gushing into the icy water was the last thing Harry consciously perceived as he sunk down to the bottom. In a last, hindbrain driven struggle for air Harry thrashed himself into a cave too small for the Inferi to venture into. This cave was instead populated by a species far older, but no less strange. These aquatic creatures also acted on instinct, on a set of instructions buried deep in genetics passed down through centuries.

Sensing a warm, live presence the creatures nearest to the cave mouth fought violently with each other to get to the potential host body first. The lucky survivor, missing a chunk out of it's tail as the price of it's victory, nosed along the prone form. Looking for a way in, and finding it in the large 'x' shaped hole in the body's abdomen.

Most of the internal organs had already been lost to the Inferi, but the creature pushed out the last of them, leaving only those protected by the ribcage. Confident of it's new home it began to secrete a thick, viscous fluid that would ensure it's continued survival. A potent formula of new genetics that would overtake the original genetics of the host form, allowing it to house the creature and strengthening it so that it would survive without some of it's internal systems.

The new genetic code in the creatures secretions quickly worked on the body of the host, modifying almost all of his current genetics, only leaving a small section of already mutated code untouched. Soon the body took in a shuddering breath, water rushing into newly capable lungs and forcing it's way out of barely formed gills. It began to heal, skin and bone and muscle knitting together, new cells dividing at a rate far beyond what it had previously been able. But, perhaps the most important changes were being made in the host body's brain: neural tissue that had been damaged by lack of oxygen was rejuvenated, and new pathways were formed, entire sections and processes created in the spaces between existing paths.

Harry's eyes fluttered open, new nictitating lids protecting his now enhanced sight from the water that surrounded him. He quickly shut his eyes again, sure that he was dreaming the watery cave filled with snake like creatures. The brush of scaled bodies along his limbs soon had him opening them again.

Then, he panicked. Because human beings couldn't breathe under water, not even wizards. Not without out bubble head charms or partial human transfigurations. The second task had taught him that while there were ways around it, humans were still definitely not meant to spend any great length of time underwater.

Limbs flailing out in every direction, scattering the not-snakes that had crowded around him. He desperately held his breath, however, like humans weren't meant to be underwater for very long, they also couldn't repress the urge to inhale for very long. Sure that he was going to drown it took Harry an embarrassingly long time to realise that he was breathing water into his lungs and out through his gills. Not unlike the ones that had formed when he'd eaten the gillyweed Dobby had stolen out of Snape's stores for him.

Lifting a cautious hand to his neck, he pushed a finger against the sore slits. They ached fiercely, unlike those created by gillyweed, pulling his hand up to his eyes he saw the distinct lack of webbing and felt the stirrings of panic well up again. Firmly tamping down his anxiety, he looked around the cave he was in. Presumably, it was somewhere in the moat with the Inferi, who were suspiciously absent. Instead it was inhabited by hundreds of snake-like creatures, twisting and turning around each other, alternately seeming to play and fight with their fellows.

Harry lifted a hand up toward one of the nearer creatures, mesmerised by the rippling of it's fins. It appeared to noticed his curiousity and fanned it's fins out to their full span. It began looping around in the water, dancing around his hand. Harry smiled at the display, the creature was beautiful, in a way, it's rich patterning changing with it's mood and surrounding. It's colours brightened as he ran a finger down it's side.

Suddenly, Harry became aware of a feeling of jealousy and resentment permeating his mind. He'd learnt from Voldemort's repeated attacks of his mind as he slept what a foreign mind felt like. Yet this presence was even stranger than the twisted mutation that was Voldemort's mind. It was emotional and impressionistic, no hint of verbal language. Instead there were more nuances of violence and pride and anger than he had ever felt. Somehow Harry could understand every detail perfectly, and he responded without conscious thought. Sending back feelings of 'don't worry, it isn't important' and swiftly followed it with a strong burst of curiousity.

He received a feeling a great excitement, wonder and pride. The last was dual toned, both directed at Harry and the mind the emotional pulse had come from. Marvelling at the intelligence of the creature communicating with him, he forgot to be alarmed that he wasn't alone in his mind anymore. His experiences with both Snape and Voldemort had taught him the immense value of mental privacy.

A sharp nip to his outstretched finger brought him back to the present. It seemed the creature in front of him was unimpressed by his distraction. The burst of resentment and anger that came when Harry slid a finger carefully over the fins of the creature made him chuckle. And he sent back a feeling of fondness and it's okay. It seemed his new mental companion didn't believe him though, a scaled head poked it's way out of the gashes in his abdomen and hissed venomously at the creature Harry was absently stroking.

The appearance of this snake coming out of his stomach made Harry reflexively clutch at his guts. He could clearly see the raw wounds and he remembered the feeling of overwhelming pain he'd felt before he'd passed out. It's okay, don't worry, safe; the feelings bombarded him, reacting to his blind panic and fear. The snake curled its way around Harry's hand, undulating slightly as it radiated feelings of warmth, sanctuary, safe. Harry couldn't help but relax under the soothing onslaught. he'd never felt anything like that before - the bone deep certainty that something cared for him, would feel his pain and do it's best to reduce it. Partnership, solidarity, togetherness, shared. Harry basked in the feeling of warmth that suffused him, even in the bitter chill of the water. Gratitude, wonder, new, together, strong. He pushed his own feelings down the emotional bond, and soon was lost in a new world of sensation and communication. Familiarising himself with this new, nuanced language of emotions and impressions.

Harry didn't know how long he spent, exploring this new connection, communicating with and learning from his new companion. But soon he remembered why he had come to this cave in the beginning. And with that memory came the realisation that he didn't know what had happened to Dumbledore. Filled with worry for the Headmaster, he began to shift, warily testing out his limbs. He was determined to make it to the surface in one piece. Curiousity, leaving, why. The feelings pushed at the corners of his mind, and he returned with important, precious, injured, need to help, determination and the feeling of land/sky/not water that seemed to represent the world outside the lake. There was no reply for a minute, then determination, willingness, understanding, will help came flooding in.

Buoyed by his companions willingness to support his venture through the Inferi to the surface, Harry stroked his stomach in thanks. He turned to the cave mouth and began to swim. He wasn't sure how well he'd be able to fight off the Inferi, he didn't know where his wand was and he was a clumsy swimmer at best of times. He needn't have worried, as he turned toward the surface, a stream of the snake creatures swarmed out of the cave, holding back the Inferi and leaving him a clear path to the surface. Unthinkingly he sent a pulse of wonder, incredulity and thank them through the bond, he didn't know if the creature sharing his mind could communicate with anyone else.

It was quickly confirmed that it could, when every one of the snake-like creature turned their head toward Harry as he lingered, just under the surface, and splayed their fins to wave goodbye to him. A helplessly fond smile spread across his face, these creatures who couldn't communicate with him but in the most rudimentary form. Creatures that hadn't met him, or even known of his species, until only a few hours ago were better friends to him than any member of the human race that he'd met before. Promising himself he would return to the cave again in the future, and communicating as much to his companion, he broke through the surface; gasping the dank air into his lungs.