Fe is for... Fendahl

The Fendahl originated some 12 million years ago on the fifth planet of Earth's solar system. It was a gestalt creature which consisted of a humanoid core, with twelve huge snakelike feeding parts, known as Fendhaleen. It came into being when evolution took a wrong turn - leading to a creature which lived on death - consuming even its own kind. Fearing it might one day consume all living things in the universe, the Time Lords intervened and had the planet destroyed, imprisoning its remains in a time loop. However, the Fendahl core had managed to escape. It moved to Mars where it wiped out emerging life there, and then passed on to Earth. Here, it was caught up in a massive volcanic eruption in central Africa, and was apparently destroyed.

However, the skull was discovered by an expedition led by Adam Colby, and financed by the industrialist Professor Fendleman. It was brought to England, to Fendleman's home on the outskirts of the village of Fetchborough. There was a rift in space / time in the area, which the professor was studying using a time scanner. The skull had a pentagram on its crown, which acted as a form of neural relay. The Fendahl had been influencing the human race over the centuries, in order to provide a means for its resurrection. Fendleman was part of this scheme, as was one of his scientists - Thea Ransome. She also had a pentagram on her skull, and had been selected to act as the creature's new host core. Another of Fendleman's team - Max Stael - was secretly leading a black magic coven in the area, and they intended to help resurrect the Fendahl.

One of the adult Fendahleen was killed when hit with shotgun cartridges filled with rock salt. When Thea transformed into the Fendahl core - appearing as a beautiful golden being - Stael killed Fendleman. He then took his own life rather than be turned into a Fendahleen. This weakened the creature, as it needed all thirteen components to attain full strength. The Doctor was able to steal the skull, then rig the professor's equipment to create an implosion - destroying the house, the core the Fendahleen within. The Doctor then deposited the skull into the middle of a supernova, destroying it utterly.

Played by: Wanda Ventham (Thea Ransome / Fendahl Core). Appearances: Image of the Fendahl (1977).

• Second of three appearances in the programme for Benedict Cumberpatch's mum. She had first appeared in The Faceless Ones ten years previously, and would return to the programme for Time and the Rani.