The Time Monster is the fifth and final serial of the ninth season of the British science fiction television series Doctor Who, which was first broadcast in six weekly parts on BBC1 from 20 May to 24 June 1972.
The Doctor explains that Kronos is a "chronovore", a creature from outside time that feeds on it, attracted from the vortex to ancient Atlantis using a crystal trident larger than one seen to have been used by the Master.
In ancient Atlantis, King Dalios is troubled by the disappearance of Krasis and the threat to the Kronos crystal, which is guarded by the Minotaur at the heart of a maze.
When the Doctor and Jo arrive, the unnaturally long-lived King confides that Atlantis turned from Kronos and sought to end the link by which the chronovore could be controlled, by destroying the crystal, but they could only splinter it.
In the vortex, the Doctor threatens the mutually assured destruction of both TARDISes by a "time ram" in which both vehicles would occupy the same space/time co-ordinates, The Master calls his bluff, on behalf of Jo is unable to until she carries the threat out.
David Prowse would later achieve worldwide fame as Darth Vader in the original Star Wars trilogy beginning in 1977.
[6] In 2010, Mark Braxton of Radio Times felt that the serial teetered between "delightful" absurdity and "outright, galloping stupidity, and sadly it tips too often into the latter."
[7] DVD Talk's Stuart Galbraith gave The Time Monster two out of five stars, finding problems in the plot structure and Kronos.
[9] A novelisation of this serial, written by Terrance Dicks, was published in hardback by Target Books in September 1985, and in paperback in February 1986.
It was reprinted again as part of Target's Doctor Who Classics range back-to-back to Barry Letts' novelisation of The Dæmons and bound in a metallic cover.
The Time Monster was released on 29 March 2010 in a Region 2 DVD box set named "Myths and Legends" along with Underworld and The Horns of Nimon.