Disclaimer – Okay, everyone's had their turn, so here's mine. I've had a plot bunny forming for some time, ever since Saturday morning. So, with that said, here's my meager offering, but from Donnie's POV. I wrote it hurriedly, so it's not really finished. I'll probably add stuff to it later, maybe in chapters, but for your evaluation I decided to upload it.

Once again, I own nothing, other than the title and the introspective story.

Symbiont

by reinbeauchaser

In a flash, everything had changed. In a split-second, he realized a horrific truth. In fact, he had felt it coming for some time, but Donatello honestly believed he could beat it. After all, the lowly insects from the sewers did not have his intellect, his mutated genius mind, so he truthfully felt he had an advantage. He believed he could be stronger than what was happening to him.

Plus, he was sick and not quite himself.

In a split second, though, and with a sudden horrific turn of events, he realized he had been wrong, terribly wrong.

He had miscalculated.

This was not like him at all. The great mind of Donatello always allowed room for error, always allowed for miscalculations. This was why he rarely experienced them, because he allowed for them, planning in advanced, thinking and re-thinking every aspect of every problem. He had always second-guessed his calculations, imagining the what-if's and considering each angle. This was why he was always right, each and every time, but this time...this time he was wrong, so very, very wrong.

The moment April left for the bedroom, to find out what Casey had broken, Donnie had felt the change. He had noticed something going on with his leg, even before his brothers had dropped him off at April's apartment. The sniffles and the sneezes were annoying, but Don knew his brothers had a job to do and they couldn't have him along, not where he seemed to be so sick.

Nevertheless, he honestly believed he had time to figure his problem out.

However, time was something that he didn't have anymore and now...now it was too late.

The moment he felt it, the moment the change began, Don tried to call out for help. However, the pain was numbing and the way his leg swelled took him by surprise. The shock it gave him to see not only his afflicted appendage grow, but to see his other leg do likewise, scared him more than the mutations running amuck through New York City.

Then, it all became a domino affect, the speed in which his body was transforming. First, his legs changed, then his arms, next his entire body - and then finally even his mind. He could feel it, the feral wildness, and the intense hunger to consume as it all fogged his sense of reasoning. The internal struggle grew within Don so quickly and with each passing second, that the demon became stronger as it tried to take control of him.

At its onset, Don tried to remember everything his father had taught him about manipulating his environment. Yet, as the seconds ticked by, as his body began to morph, he knew it was a hopeless cause.

Had anyone been aware of his battle, they would have most certainly felt his courage, though. They would have seen Don in a completely different light and come to understand that he embodied Leo's ninjitsu skills and Raph's determination. Don always felt he was a combination of his two brothers, but he was far too passive and too intelligent to voice such understanding.

Maybe that was a mistake.

No, Don knew it wasn't a mistake; it was better for Leo to lead and Raph to charge ahead like the proverbial bull in a china shop. In that way, it left Don to do what he loved best – and that was being a problem solver.

The only problem was he couldn't figure this one out.

As the creature inside grew bigger than Don's resolve, as it forced him from the couch, Don managed to cry out once, to beg for help. But the moment he did, he realized the last person he wanted to see him like this was – April.

Fear gripped at him, now, a terrible agonizing fear that in some way, some how he might hurt her. He could not hurt April; he wouldn't...would he? He was bigger than this – this thing he knew he was turning into. He had to control it.

"My arms, my legs, I'm - growing, I'm - even taller! Now, I can – actually touch the ceiling!" he whispered, almost in wonder,as he forced his head down, to keep from breaking the ceiling light. But he then cowered as he heard the pounding of feet, as his friends barreled worriedly into the living room, answering his call of distress.

He huddled in the corner, now, afraid to show his face, knowing well his enormous size would give away his transformation. He didn't know what he looked like and he was afraid.

He then turned and looked at them. However, his eyes seemed strange, as if seeing them differently somehow. Donnie heard April say something, but by this time, his mind was incapable of understanding her. He saw her lips move and he knew she said something. Casey's face grew large with shock, but Donnie could only mutter and even with that, he wasn't sure if he was making any sense, "Help me!"

Even his voice sounded strange to him.

Suddenly, Don realized that he didn't want them to see him like this, because he knew something else was happening to him.

He didn't – trust himself anymore.

Donnie could do nothing but run, now, begging April and Casey to go away and not to follow him. Something within that last bit of intelligence, the fragment that was still Donatello, told him that he had to 'go down' in order to escape, to keep his friends safe.

As Don ran and as he raced down the stairs to the basement below, the last vestiges of who he was, the brainiac, the passive ninja and inventor, fell away as the demon within took complete control.

And in that moment, the great Donatello - died.