Planet of the Spiders

Notes

• This story was novelised by Terrance Dicks and published by Target Books in 1975 (under the title "Doctor Who and the Giant Spiders").
• The final story of Season 11 (entitled The Final Game) was originally intended to write out the character of the Master, with the villainous Time Lord sacrificing his life to save the Doctor's. Due to the tragic death of actor Roger Delgado, script editor Terrance Dicks abandoned the project in favour of a new story, which eventually evolved into Planet of the Spiders.
• This story marks the final appearance of Richard Franklin as Mike Yates. Franklin would reprise his role in The Five Doctors (1983) and Dimensions in Time (1993). After his departure from the series, Franklin would go on to become a director of many stage plays and television shows.
• This story was the second and last appearance of the "Whomobile".
• The character of Harry Sullivan, the UNIT medical officer, is referred to by the Brigadier who calls for him when the Doctor falls into a daze after staring into the crystal. Sullivan would not actually appear on screen until Robot, where he was played by Ian Marter.
• This story introduces the character of K'anpo Rimpoche, the previously unnamed Time Lord hermit from the Doctor's childhood, first mentioned in The Time Monster. K'anpo has the power to travel through time without the use of a TARDIS, to make a corporeal projection of a potential future incarnation (Cho-Je) of himself, and to stimulate the regeneration process of another Time Lord. Whereas a Time Lord was seen to travel without a TARDIS in Terror of the Autons and the Doctor has met two future potential incarnations of himself: the Watcher in Logopolis (1981) and the Valeyard in The Trial of a Time Lord (1986), no other Time Lord has been shown to stimulate the regeneration process (although it can be argued that the Time Lords stimulated the Doctor's regeneration in The War Games; and that the Doctor's companion Romana may have stimulated her own regeneration or projected possible future incarnations for the Doctor to choose from in Destiny of the Daleks). K'anpo was referenced again in the Fourth Doctor serial State of Decay as the man who told the Doctor about the legends of the Great Vampires.
• This is the first story to feature a Time Lord (other than the Doctor) regenerating on screen. To date, the only other Time Lord that has regenerated in a television story is Romana in Destiny of the Daleks (1979).
• The Third Doctor's last words were "A tear, Sarah Jane? No, don't cry. While there's life, there's..."
• The Spiders of Metebelis Three make further appearances in the short story Return of the Spiders by Gareth Roberts and a brief appearance in the Eight Doctor Adventure The Eight Doctors by Terrance Dicks.
• The Eighth Doctor Adventures novel Interference has the time-travelling voodoo cult Faction Paradox changing history so that the events of this story never happen and instead having the Third Doctor regenerating on a planet named Dust after being shot. This paradox has not yet been resolved in the spin-offs, and its canonicity is unclear.