The one with killer entrails.
A spaceship arrives on Earth and two beautiful, golden-skinned humanoids step out, saying that their ship is damaged and that, in exchange for time to lay over and make repairs, they will offer humanity a substance called Axonite, which can cause animals to grow to huge sizes, ending world hunger.
However, the Doctor is sceptical and discovers the true form of the Axons - hideous tentacled monsters who have been invited to Earth by the Master to drain the Earth's energy. They, their ship and the Axonite are all in fact one single parasitic entity.
The Master is captured, but offered his freedom in exchange for helping UNIT and the Doctor defeat the Axons. The Master's plan is to use the TARDIS to absorb energy from a nearby nuclear power station, then release it all at once into Axos - but this is an inherently dangerous plan and the Doctor has a better one. He and the Master travel with the TARDIS into the centre of Axos, where the Doctor traps the ship and Axons in a time-loop from which it can never escape - but unfortunately, the Master does.
- All There in the Script: Winser's first name is Malcolm.
- Beauty Equals Goodness: Subverted. The Axons may be pretty and offer their technology to Earth, but it's all part of a Wounded Gazelle Gambit.
- Combat Tentacles
- Deadpan Snarker: Roger Delgado seems to be having a great time with some of the lines The Master gets in this serial. Check the page quote.The Master: [advising the Brigadier how to survive a nuclear blast] You could take the usual precautions...sticky tape on the windows, that sort of thing.
- Disposable Vagrant: Poor Pigbin Josh is the Axons' first victim.
- Fake Defector: The Doctor.
- Glam Rock: The aesthetics of glam rock had a very big influence on the look of the Axons. It was the early Seventies, after all.
- Hilarious Outtakes and Deleted Scenes: This is one of the few Doctor Who stories for which material from the original studio recording exists, so mistakes such as the Doctor missing his cue, as well as extra scenes cut from the final programme, can be seen on the DVD.
- Hive Mind: The seemingly individual Axons are all part of the same entity.
- Ironic Echo Cut: The Doctor says he's happy that the Axonite will be kept in Great Britain only. Cut to Chinn being forced by the UN to distribute the Axonite over the entire world...
- Jerkass: Chinn.
- Laser-Guided Amnesia: The Doctor reveals (to the Master, no less) that the Time Lords have blocked his knowledge about time travel to prevent him from repairing the TARDIS and escaping his exile on Earth.
- Light Is Not Good: Gold and orange are the Axons' primary colour palette and they turn out to be evil.
- Magical Particle Accelerator: Providing enough energy for time travel? Check!
- The Master
- Obstructive Bureaucrat: Right wing politician Chinn.
- Oh, Crap!: The Doctor when his trusty Venusian Akido has no effect on the Axos!Filer
- Organic Technology: The spaceship they arrive to Earth in. Considering that even the ship is part of the Axos hive mind, this makes sense.
- Panty Shot: Jo gets one as she and the Doctor are escaping from Axos.
- Real Life Writes the Plot: During location filming, the weather proved highly variable, ranging from snow at the start of the week, through fog and finally to sunshine on the final day. To explain the inconsistency, Terrance Dicks assigned a new line of dialogue to Corporal Bell which noted that Axos' arrival had prompted freak weather conditions.
- Right for the Wrong Reasons: Chinn is right about not wanting the Axonite to be distributed over the entire world, though it's because he's greedy, rather than because the Axonite is dangerous.
- Shaped Like Itself: "Well, it's perfectly simple, Brigadier. A time loop is, er. Well, it's a time loop." The Doctor then pauses before trying again to explain it.
- Spot the Imposter: One of the Axons takes on the form of Bill Filer. The imposter gets in a struggle with the real Filer and the Doctor is unsure of which one to help, until the real Filer calls him "Doc".
- Title Drop: Subverted by Chinn, as while he's ranting about the Doctor's lack of clearance and dossier calls him "Doctor...(Beat)...whateverisnameis..."
- The Doctor drops the title of the serial in the last episode, though.
- Trojan Horse: The Axons provide the human race with an alien fuel called Axonite, seemingly to help us with our energy crisis but actually to destroy us.
- The Unintelligible: Pigbin Josh.
- The X of Y