Heat

Some species fed on heat for sustenance. These included the Dreilyn, (COMIC: A Cold Day in Hell!) the Hyban, (PROSE: The Frozen) Phoenixes (AUDIO: Frostfire) and the Vostok. (COMIC: The Return of the Vostok) On other species, heat had the opposite effect of weakening them; these included Chalderans (COMIC: Under the Volcano) and Ice Warriors. (TV: The Seeds of Death) Silurians were vulnerable to changes in temperature. (AUDIO: Call to Arms)