"A quick pop back to see the Coronation, you said." Tegan could feel the changes rushing through her already, but still she spoke, venting her frustration, desperate to maintain her sense of self.
"Boating in the Caribbean with cosmos and back on Monday for work, you said." And she'd believed him this time.
She couldn't see the Doctor any more, so intense was her pain; her vision was filled with throbbing lights and blinding white streaks that sliced into her mind. She knew he was there though, still bound and cuffed in the rear of the lab, watching helplessly as they changed her, customized her. The alien technology screamed around her as her skin began to bubble, swell and change.
Landing in the middle of the Vietnam war instead of Buckingham Palace was not, it had to be said, a complete surprise to Tegan given the Doctor's past record. At first, it had made her laugh, the giddy emotion laced with nostalgia that clung to the back of her throat, cloying, bitter. The laughter had ended quickly as napalm and death erupted around them, separating them from the TARDIS, the jungle dripping with fiery, liquid death. They'd lost Turlough first, before the aliens, before all this.
Amid all the pain, all the tearing and the seizures that racked her body, something tickled at the base of her neck.
"You can't do this to me! STOP IT!"
She hadn't understood the name of the aliens that held them, that had dragged them back to their ship deep in the jungle. There had been too many explosions, bugs and horror. Even in the still of the laboratory in the bowels of the vessel, she'd only had a chance to hear a whisper: 'Her DNA has been contaminated; candidate suitable for extraction."
Then the pain had begun.
Now the tickle sensation was growing and she felt it unravel and burst. It blossomed in the back of her mind, uncurling, looping outward in great logarithmic furls, consuming her mind, devouring her body.
"Think of home," was all the Doctor had managed to say to her before she was pulled from him and chucked into the hulking machine that embraced her with organic tendrils of green and purple.
Everything was distant now... the pain was receeding, she tried to dig mental fingernails into the ether around her, but she felt herself slipping away, dispersing, washed away in the white light. She made one last desperate cry in a silent, ragged mental voice:
home
The thought echoed in her head, but her mind was no longer her own.
The Doctor stared up at his companion, helpless as her limbs bled and merged in a frothy mess of flesh and blood that wove and seeped into a new form, a larger form, one with no legs, no arms, no sign of humanity. As he watched, horrified, Tegan's shoulders and head merged into a giant, scaly hood that shimmered, the green skin shimmering it a baptism of its own blood. The Mara smashed its way clear of the machinery and towered above them all.
The Doctor realized that he was slipping into shock. Distantly, amid the chaos, he heard the aliens speak calmly to each other, as if observing a tennis match. "Manifestation nearly completed; allow time for acclimation. Provide suitable sustenance. There is very little time until the Myrmidon arrives. If this creature can't defeat it, this world is doomed."