Jayce/Mel/Viktor
We had used it on plants; initial testing proved promising, but not without risk (the plants flourished, then died, and the hexcore seemed to exhibit semi-sentient qualities). I reached a point where I was more comfortable with that risk, and the results -- well, I'm sure you saw my hand. My leg is the same now.
I'd locked the laboratory, but Sky had a key. I regret every step that I took to make what happened happen.