Vrund

The  were a civilised race, according to the Fourth Doctor. Usually they existed in symbiosis with another race on their planet. However, the Puppeteer somehow made it to Earth in the 19th century and was forced to bond with a human. The human was driven crazy by the bonding, and the Puppeteer continued to bond with humans, eventually following them on their travels into space. (PROSE: Puppeteer)