Tom Baker
Image Of The Fendahl

A human skull is found by archaeologists. To determine its age it is subjected to a time scanner experiment and found to be over twelve million years old. The TARDIS is drawn to Earth by the Time scanner.

The skull is an artefact of Fendhal, an ancient creature that feeds of the life-force of others. Using Thea Ransome, who is unaware she is a medium, the entity is able to materialise on Earth.

Thea is eventually transformed into the Fendahl, and a group of acolytes assembled by black arts practitioner Maxillian Stael are transformed into the Fendahleen.

The Doctor is able to show the surviving people how to protect themselves using rock salt. Using the time scanner to cause an implosion the Doctor destroys the Fendhal. He and Leela take the skull to be jettisoned near a supernova.