Like gross little spies for the Cybermen, Cybermats are insect/rodent-like cybernetic beings dispatched to infiltrate, gather intel, steal electricity and bite humanoid ankles. In New Who episodes like ‘Closing Time’ they were shown to contain organic components.
Podcast C043 The Wheel in Space
The most convoluted Cyberman plot to date VS. The least professional space station crew ever
Podcast C037 The Tomb of The Cybermen
Racist Space-archeologists unearth a fortune in Cyber-stencils in this legendary serial.