Nemesis

Nemesis was a statue made of validium that had landed in Windsor in 1638 and was discovered by Lady Peinforte. The Doctor launched Nemesis into space in a rocket-powered asteroid. Its orbit had brought it near Earth every 25 years, each time influencing disasters, finally returning in 1988. It was used by the Doctor to destroy a Cyberman space fleet. (DW: ''Silver Nemesis)