The Horns of Nimon

In the serial, minotaur-like aliens called the Nimons plot to invade Skonnos by creating a tunnel in time and space linked between two artificial black holes.

It resides inside a labyrinthine Power Complex on the planet Skonnos, and communicates only with the Skonnan leader, Soldeed, who reveres the Nimon as a god.

The Nimon demands a regular tribute of young people, who are flown in from the nearby planet Aneth, as well as a supply of hymetusite crystals.

On Skonnos, the Nimon is enraged by the delayed sacrifice and threatens to withhold the promised armaments that will help rebuild the Skonnan Empire.

It is revealed that the Nimon are a parasitic race who travel via artificial black holes between planets, draining their resources, before moving on to conquer new worlds.

[1] In the closing scenes of The Horns of Nimon, the Doctor alludes to the Ancient Greek story by reminding Seth to paint his ship white (in reference to Theseus's return to Athens), and insinuates that he was personally involved in the original events of on Knossos, when he "caused quite a hoohah … Other times, other places".

[2][3] Paul Cornell, Martin Day, and Keith Topping gave a mixed review of the serial, stating "With its cheap design work, and a wonderfully watchable OTT performance from Graham Crowden, The Horns of Nimon is by turns brilliant and dull".

Doctor Who: The Television Companion's David J. Howe and Stephen James Walker noted that the serial had acquired a low reputation but they considered this to be undeserved.

[5] Patrick Mulkern of Radio Times was very critical of the serial which he described as "a turgid quagmire of vapid characters, amateur dramatics, mirthless antics and clattering sets".

[6] In A Critical History of Doctor Who on Television, John Kenneth Muir opined that Read's use of classical allusions to Greek mythology served little purpose, but noted that the December broadcast slot of The Horns of Nimon coincided with the British panto season, obliging the scriptwriter to include in-jokes.

[1] Writing in 2017, Carey Fleiner linked the mythological theme of The Horns of Nimon to the idea of the monomyth popularized by the author Joseph Campbell in his 1949 book The Hero with a Thousand Faces.

[3] Den of Geek's Andrew Blair selected The Horns of Nimon as one of the ten Doctor Who stories that would make great musicals.