The Sycorax whip was a weapon used by Fadros Pallujikaa on Daniel Llewellyn and Richard Blake.
Biology
The Sycorax whip was basically a brown rope with a handle housing the micro-fusion generator. It would typically kill by lashing the end at a victim's neck. During this process, the rope would illuminate blue and show the victims bones slightly in the same color, similar to a Dalek's death ray. This destroyed all cells in the human body as well as disintegrating clothes, leaving only burned bones behind. (TV: The Christmas Invasion)