Inferno (1970) - a movie.
The Third Doctor and UNIT are called in to investigate a murder at Project Inferno, an effort to drill through the Earth's crust to harness great energies within the planet's core. It transpires that the drilling is producing a green ooze that transforms all who touch it into savage humanoid creatures called Primords, who can only be killed via extreme cold. Unbeknownst to anyone, the project leader, Professor Stahlman has been infected and is in the early stages of the change. After quarrelling...