Living metal

Living metal was a metal which was able to grow.

History
In an example of a naturally-occurring living metal lifeform, the Magnedons, one of the lifeforms native to Skaro, was a crocodilian reptile with living metal flesh. It was, as a result, magnetic. (PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe)

On Earth, living metal was discovered by Professor J. P. Kettlewell. He used it to create the Experimental Prototype Robot K1. (TV: Robot)

The Founders of the Time Lords utilised the living metal validium to construct Nemesis. (TV: Silver Nemesis) The outer plasmic shells of Battle TARDISes were living metal, able to morph into shields or any number of predetermined gun emplacements. (PROSE: Engines of War) The architectural reconfiguration system of the Doctor's TARDIS was also built from a type of living metal. (TV: Journey to the Centre of the TARDIS)

Caw was made entirely from living metal. (TV: The Infinite Quest)

The Panjistri used living metal in the construction of their spaceship Kandasi and their hovercraft. (PROSE: Timewyrm: Apocalypse)