History Trivia / DoctorWhoS9E4TheMutants

* MagnumOpusDissonance: Bob Baker felt this was the best story he and Dave Martin wrote, although Martin admitted that the execution wasn't the best.

** A subplot about cloning was removed from the latter portion of the adventure, as it was felt to be overly complex.
** To effect Ky's transformation, the Doctor initially had to turn the crystal into a liquid form and inject it into Ky's neck; as scripted, the Solonians' final mutated form was an iridescent globe.

** Geoffrey Palmer had previously played [[Recap/DoctorWhoS7E2DoctorWhoAndTheSilurians Masters]], and would later play [[Recap/DoctorWho2007CSVoyageOfTheDamned Captain Hardaker]].

** Creator/ColinBaker was considered for Cotton. He would later play commander maxil in arc of infinity and the Sixth Doctor from then on.

** Creator/ColinBaker was considered for Cotton. He would later play the Sixth Doctor.

* NamesTheSame: Cotton is played by Rick James, but not ''that'' Music/RickJames.

* RenamedToAvoidAssociation: The Mutts were originally named Munts, until Creator/TerranceDicks learned that the word was a slur in South Africa.

* HostilityOnTheSet: The bad blood between Creator/JonPertwee and director Christopher Barry, which had started when the two worked together on the previous season's [[Recap/DoctorWhoS8E5TheDaemons "The Dæmons"]] didn't improve any during the production of this story, and resulted in Barry not working again on the series until Pertwee left and was replaced by Creator/TomBaker.

* ActingForTwo: Garrick Hagon, who played Ky, also served as the voice of the Skybase public address system.

* HostilityOnTheSet: The bad blood betewen Creator/JonPertwee and director Christopher Barry, which had started when the two worked together on the previous season's [[Recap/DoctorWhoS8E5TheDaemons "The Dæmons"]] didn't improve any during the production of this story, and resulted in Barry not working again on the series until Pertwee left and was replaced by Creator/TomBaker.

** George Pravda had previously played [[Recap/DoctorWhoS5E4TheEnemyOfTheWorld Denes]].

** Geoffrey Palmer had previously played [[Recap/DoctorWhoS7E2DoctorWhoAndTheSilurians Masters]].

* AbilityOverAppearance[=/=]ColorblindCasting: Cotton was originally a Cockney, but Christopher Barry decided to cast a black actor in the role. Without altering his speech patterns.

* AbilityOverAppearance: Cotton was originally a Cockney, but Christopher Barry decided to cast a black actor in the role. Without altering his speech patterns.

* CreatorsFavoriteEpisode: Bob Baker felt this was the best story he and Dave Martin wrote, although Martin admitted that the execution wasn't the best.

* YouLookFamiliar: George Pravda had previously played [[Recap/DoctorWhoS5E4TheEnemyOfTheWorld Denes]].

* YouLookFamiliar: George Pravda had previously played Denes in [[Recap/DoctorWhoS5E4TheEnemyOfTheWorld The Enemy of the World]].
** Christopher Coll had previously played Technician Phipps opposite [[Recap/DoctorWhoS6E5TheSeedsOfDeath The Seeds of Death]].
** Geoffrey Palmer had previously played Masters in [[Recap/DoctorWhoS7E2DoctorWhoAndTheSilurians Doctor Who and the Silurians]].

* RaceLift: Cotton wasn't supposed to be black, but director Christopher Barry cast a black actor in the role.
* WhatCouldHaveBeen: A subplot about cloning was removed from the latter portion of the adventure, as it was felt to be overly complex.

* RaceLift: Cotton wasn't supposed to be black, but director Christopher Barry cast a black actor in the role. He also didn't change the character's Cockney speech patterns.

* [[NamesTheSame Name's The Same]] - Cotton is played by Rick James, but not ''that'' RickJames.