Meet Verina Gray, a scientist who was working with creepers. She was trying to modify the mind of the creeper to be less aggressive, almost friendly. She had been trying to achieve this goal by creating a machine, one that would allow her to hook her mind up to that of the creeper. When she finally tested it, something went terribly wrong.
She attached the head-pieces the the creeper and her self - proceeding to turn on the machine. When she did so, she did not know she had made a mistake in building the thing. One little mistake, one little crossed wire that would change her life forever. The machine, instead of just transferring her mind waves into the creepers brain, some of the creeper's went into hers as well. A trade, in the stead of a gift.
At first, the creepers mind cells had no effect on Verina whatsoever. Then, over time, those closest to her began to notice changes. She began to grow more distant, almost hating, to those around her. Then the big changes happened.
The creepers mind cells thought the body of the creeper they had once been in was being attacked by invaders. It began to take over the body, bit by bit. It started to kill off some of the human cells, replacing them by new, creeper cells. It was a slow, painful process, and there was no cure. If they had tried to remove the creeper part of her brain, it would leave her short of brain cells, killing her. The creeper that had her mind inside had been slain long ago, before they knew of Ms. Gray's.... condition. She had no choice but to live with it. But she began to fell urges to harm those around her. These grew so strong, she had to make a big choice. To leave forever, living in complete isolation.
She still roams the distant woods, but although she still looks half human, she is a monster. The killing urges of a creeper, combined with the great intelligence of an ingenious scientist gone one step to far...