Validium

Validium is a living metal able to think for itself and change its shape.

The Doctor allowed a piece of Validium to fall to Earth and then allowed Lady Peinforte to construct a statue of herself out of it making it the Nemesis Statue. The Doctor launched Nemesis into space in a rocket-powered asteroid, though the bow and arrows were kept on Earth. Its orbit had brought it near Earth every 25 years, each time influencing disasters, until it finally returned 1988.


 * The Validium may have been able to telepathically create the disasters.

The Doctor used the Nemesis Statue to destroy the Cybermen ships for the invasion attempt of 1988.