The Yeti

The Yeti are a huge fur-covered robot controlled by a sphere in their chests. They are controlled by the Great Intelligence (the Great Intelligence was exiled from another dimension. It is an entity that used its power over human minds and the Yeti in their attempts to rule Earth). The Doctor first encountered them in the Himalayas, and then again in London Underground where they had web guns to defend themselves.  On both occasions the Yeti were deactivated by the destruction of the central pyramid of spheres controlled by the great Intelligence. The Doctor only had one further battle with the Yeti, an that was in the Death Zone on Gallifrey.  

The Yeti were in The Abominable Snowmen, The Web of Fear and The Five Doctors.

A Yeti Roar