Death whip
The Sycorax whip was a weapon wielded by Fadros Pallujikaa.
Properties
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)
History
During the Sycorax invasion of Earth on Christmas 2006, Pallujikaa used his whip to murder Daniel Llewellyn and Richard Blake, who were part of a delegation of humans he had teleported aboard his ship. Shortly afterwards, he attempted to repeat the process on the newly-regenerated Tenth Doctor, who had emerged from the TARDIS, only for the the latter to grab his whip a split-second before it came into contact with his neck. (TV: The Christmas Invasion)