Eustace (Image of the Fendahl)

"Eustace" was the nickname for an apparently Human skull found in Kenya by Dr. Fendleman, who had discovered a "sonic shadow" in the area. It was found in the remnants of a volcano. Fendleman discovered two anomalies connected with the skull. It was twelve million years old, much older than archaeologists had estimated Humans had existed. For another, X-rays revealed a pentagram-shaped pattern in the crown of the skull. Fendleman experimented with the skull, determined to find out its secrets.

In actuality, Eustace had originated as the skull of a Fendahl Core and still possessed vestigial life. Glowing with power, it drained life from the Doctor. Fendleman's employee and the leader of a coven, Maximillian Stael, used it as centrepiece of a ritual successfully attempting to imbue Thea Ransome with the power of the Fendahl, turning her into another Fendahl Core. Taking the skull, the Doctor put it into a lead-lined box and took it into the TARDIS, so he could throw it into the heart of a supernova, in the constellation of Canthares in order to destroy it. (DW: Image of the Fendahl