an Entity references as follows:
The Gunfighters is the seventh serial of the third season in the British science fiction television series Doctor Who, which was first broadcast in four weekly parts from 30 April to 21 May 1966. The serial is set in and around the town of Tombstone, Arizona, in the Wild West. In the serial, the time traveller the First Doctor (William Hartnell) and his travelling companions Steven Taylor (Peter Purves) and Dodo Chaplet (Jackie Lane) get themselves involved with the events leading up to the Gunfight at the O.K. Corral.