Fragging wonderful. Black ice could kill by inducing lethal biofeedback in a decker's physical brain. Heart stopping, brain creasing to function as the victim convulses into a series of seizures. Jane had seen it happen once, and that had been one time too many. Psychotropic black ice could do far worse than kill. It planted subliminal fears into the decker's mind. These ranged from relatively harmless phobias like aversion to entering the Matrix all the way up to mania and paranoia, which could result in the decker jacking out and going berserk, killing everyone in the immediate vicinity. She did not want this ice to touch her.