Molten ice pool
From Tardis Wiki, the free Doctor Who reference
Molten ice pools were a common feature of the Spiridon surface. They acted as a natural spring for the planet's icy core. The ice was sub-zero but remained semi-liquid. The Third Doctor and a Thal group pushed two Daleks into a pool. The Daleks were killed by the sudden shock of cold. (TV: Planet of the Daleks)
