Nemesis (Doctor Who)
Nemesis, also known as Silver Nemesis, was a statue forged by Lady Peinforte in 1638 from an asteroid made of the living metal validium. The Doctor and a force of Roundheads battled Peinforte, and the Doctor was able to launch the Nemesis into space. Unfortunately, its trajectory allowed it to orbit near Earth every 25 years, influencing disastrous events. Further, the statue's bow and arrow remained on Earth, providing a way for it to be tracked; the bow wound up in the hands of the Nazis, while Peinforte used the arrow to travel in time, arriving when the Nemesis would return to Earth.
In 1988, it returned, and became the target of neo-Nazis, Lady Peinforte, the Cybermen and the Seventh Doctor. Eventually, Peinforte merged with Nemesis, and the Doctor used the validium statue to destroy the Cybermen's attack fleet in space.