The one with Cthulhu aliens electrocuting people and tons of devilry.
Written by Matt Jones.
Rose and the Doctor find themselves in a space base, but the TARDIS seemed strangely reluctant to materialise (bad sign number one). Rose points out that they can hop back in and go somewhere else if they think there's going to be trouble, but neither of them can keep a straight face at the idea. They venture inwards and find a wall with "Welcome to Hell" written on it (bad sign number two), along with a series of symbols that not even the TARDIS can translate, which means the language must be impossibly old (bad sign number three). To top it all off, Rose's super work-anywhere mobile phone has no signal (bad sign number four).
They're soon introduced to the Ood ("We must feed... we must feed... you, if you are hungry"), a "slave race" linked by a telepathic field who communicate with others via orb-shaped translators. Next in line are the base's human crew, who are suitably astonished at these two strangers appearing out of nowhere and having no idea where they are. It turns out the planetoid they're on is far too close to a black hole to still be intact: something at its center is creating a gravity field (complete with a funnel for the ship to fly down) which holds it in place, and the crew are drilling to the core to find out what. The Doctor is delighted at the idea of a bunch of humans choosing to live in such a desolate place just "because it was there" and promptly hugs the ship's captain. However, the place also turns out to have massive earthquakes... one of which has just sent a chunk of the base's storage space falling into a chasm, including the TARDIS.
The Doctor and Rose deal with the idea of being trapped in that time and place forever. They discuss mortgages and whether or not they'd live together. Suddenly, they and everyone else start to notice strange glitches with the intercoms and the Ood's translator devices. When they investigate, the Ood's telepathic field goes berserk — they're screaming inside their heads. Or something's screaming at them. Right on cue, they all start chanting ominously in unison.
Toby, the crew's archaeologist, is busy examining some artefacts when he gets singled out for special treatment by a strange, whispery voice.
Toby looks — and sees nothing... until he looks in the mirror. The symbols from the shards he was inspecting have moved onto his skin, and his eyes are bright red. When Trainee Maintenance Scooti Manista questions the computer about an unauthorized opening of the airlock (with no space-suit being logged out), she's astonished to see Toby walking on the planet's surface unprotected... before he telekinetically shatters the window, pulling her into space. The others find only a shell-shocked Toby and mournfully watch Scooti's corpse drift out of sight.
When the drill finally reaches the planet's core, the Doctor talks his way into being allowed to go down in the capsule along with science officer Ida. They find the ruins of an ancient civilization and an enormous, imposing seal covered with the same markings. Right on cue, it starts to open, as the Ood rise up as the "Legion of the Beast" and the planet starts trembling in its orbit.
"The Pit is opened... and I am FREEEE."
- Action Film, Quiet Drama Scene: The Doctor and Rose discussing what they'll do if they can't get the TARDIS back.
- Adventurer Archaeologist: Toby is a aversion. He's not a soldier or anything like that. He's just here to translate the weird language.
- Artistic License – Physics:
- The event horizon of the black hole is visible, but within it is a visible corona, flickering and jumping like a bonfire. Since light can't escape back beyond the event horizon, no such corona should be visible... but damned if it isn't beautiful.
- Also, there is nothing impossible about the concept of orbiting a black hole. Black holes usually have the same mass as suns, just a lot denser, so they only become inescapable as you get so close that you'd be inside the former sun. Granted, it is possible for the black hole to have enough mass to make their current orbit impossible, but the Doctor, who really should know better, reacts to the concept itself of ever orbiting a black hole with "But that's impossible!".
- Particularly bad, since it's widely suspected that the stars in the Milky Way galaxy are orbiting a central supermassive black hole.
- A close analysis reveals that what the planet is actually doing is staying suspended in place above the black hole, even as the material of the accretion disk blasts over it as it plunges inwards. This absolutely would be impossible, thus justifying the Doctor's surprise, but the script seems to have chosen the worst possible explanation for what's going on.
- The Doctor claims that something existing before the universe is impossible. Thing is, it's theoretically possible that the singularity was originally a universe all its own that collapsed into a single point that later became the big bang, something the universe might have done an indefinite number of times and might do again. Proven? No. Possible? Possibly.
- And again, this is especially frustrating since the existence of a previous universe is a plot point multiple times in the Extended Universe; it's where the Great Old Ones (including the Nestene Consciousness and the Great Intelligence) came from.
- BBC Quarry: The first use of one in the modern series.
- Beyond the Impossible: Lots of impossible things happen on "The Impossible Planet".
- The Doctor can't read the writing on the wall, which means the TARDIS can't translate it. This should be impossible, and the Doctor even says that the writing is "impossibly old".
- The planet itself is hovering above a black hole, which the Doctor can't figure out either.
- The Ood's telepathic field reaches "Basic 100", itself impossible, and it doesn't kill them.
- Call-Back: The Ood are like a mix of the Monoids and the Sensorites. They even come from the same star system as the Sensorites.
- Cthulhumanoid: The Ood, with their face tentacles.
- Creepy Monotone: "He is awake." "He bathes in the black sun."
- Cue Card Pause: "We must feed... we must feed... [bonks translator] you, if you are hungry."
- Death Glare: Once the Ood get possessed, they start doing this en masse.
- Deadpan Snarker: One of the humans mocks the computer's automated messages. Then it starts saying things it wasn't programmed to...
- Demonic Possession: The Beast possesses Toby; there's the red eyes, the creepy markings, Voice of the Legion, the only thing missing is speaking in tongues.
- Doom Doors: It happens every time one of the doors are opened and closed. It lends to the eerie atmosphere.
- Dramatic Space Drifting: Scooti's body does this when the others discover she's dead, especially when her body is pulled into the black hole.
- Dug Too Deep: The Plan is to find the power source beneath the surface. To do that they're digging.
- E = MC Hammer: Various (including Maxwell's equations of electrodynamics) scribbled on the tables in the canteen.
- Eldritch Location: The planet, Krop Tor, which is Valtino for "The Bitter Pill". The laws of physics are not working right; neither the local scientist nor the Doctor can make sense of it.
- Evil Phone: Rose's upgraded phone fails to work for the first time... until she gets a call from something that calls itself the Devil.
- Evil Sounds Deep: The Beast is voiced by Gabriel Woolf, who played Sutekh in "Pyramids of Mars".
- Explain, Explain... Oh, Crap!: The TARDIS is parked in a storage cupboard a few sections away, the section that was hit by the earthquake. Cue a mad dash from the Doctor, to find the TARDIS is in fact gone.
- Explosive Decompression: Averted; Scootie is launched into space (by Satan, sort of) when the section of the base she's in gets shattered, and her body is still completely intact; though a) this is a family-friendly show, so there was never going to be anything too gruesome, and b) her corpse is getting pulled into a Black Hole (hence the episode title, as said planet maintains a steady orbit around said Black Hole), so will likely result in "Implosive Compression" before long.
- Foreshadowing: Among the possessed Ood statements is that the Beast has "woven himself into the fabric of your lives". The next episode expounds on that statement.
- Happiness in Slavery: The Ood supposedly live only to accept orders. If they are not given them then they do nothing. Rose is naturally disturbed by this.
- Humans Are Special: The Doctor in general (and the Tenth Doctor more specifically) usually feels this way, but the use of the trope in this episode is too adorable to leave out. He loves how they came out to this Eldritch Location "because it was there". He also says they're mad and should leave right away.
- I Don't Like the Sound of That Place: The planetoid is called "The Bitter Pill". Not even a black hole wants to swallow it.
- I Have Many Names: Which will be listed, at length, by a whole crowds' worth of Creepy Monotone possessed Ood.
- I Need a Freaking DrinkJefferson: Come on. I don't often say this, but I think we could all do with a drink.
- In Harm's Way: Rose jokingly suggests she and the Doctor leave at the first sign of trouble. They both crack up laughing.
- In Space, Everyone Can See Your Face: The spacesuits include internally lit helmets, naturally. The way the lighting casts shadows on the wearer's lower face gives the impression of a skull.
- Internal Homage: This story is a loving homage to "The Sensorites": the appearance of the aliens, a starship crew stuck in circles around an unexplained celestial body, the Doctor and his companion(s) almost being forced to live out their lives there, etc. The Tenth Doctor would later confirm that the Ood and the Sensorites are from neighbouring planets.
- Leaking Can of Evil: The Beast is able to possess people and interfere with electronics while still imprisoned.
- Mark of the Beast: The stuff on Toby after he's possessed isn't Sharpie; it's demonic.
- Me's a Crowd: The Beast possesses all the Ood at once.
- Noodle Incident: A rare Played for Drama variant:Possessed Toby: Mr Jefferson, tell me, sir: did your wife ever forgive you?
Jefferson: ... I don't know what you mean.
Possessed Toby: Let me tell you a secret. She never did.
- Number of the Beast: All over the place.
The Doctor: ...you'd need a power source with an inverted self-extrapolating reflex of six to the power of six every six seconds.
- This conversation near the beginning of the episode:
Rose: That's a lot of sixes.
- The name of the base, SB6, is shown melting into 666 in one of the TARDISodes. The Ood go to work to the sound of Ravel's Bolero, which Torvill and Dean famously skated to in the 1984 Winter Olympics — and received perfect 6s for artistic impression. As an extra metatextual touch, the official web site's Fear Forecasters gave "The Impossible Planet" a Fear Factor score of 3/6/6/6 — on a scale that usually only goes up to 5.
- And finally, the two halves of the story were released on either side of 6/6/06.
- Oh, Crap!:
- While Rose is laughing about the "welcome to Hell" sign, the Doctor's already freaking out about the fact that he can't read the language underneath it.
- Danny's reaction on seeing the Ood's telepathic field level increasing, right to level 100, where they should apparently be brain dead.
- Percussive Maintenance: There is a Running Gag of the Ood saying something unsettling, then bonking their translator before saying something much less unsettling.
- Poetry: Upon seeing Snooki's body, Jefferson is compelled to (mis)quote Thomas Babington Macaulay's Horatius at the Bridge as a eulogy.
- Red Eyes, Take Warning: They mark Toby as possessed. And the Ood. All of them.
- Red Shirt: There are two members of the crew who don't get names or lines at all. A possessed Ood kills one of them.
- Retro Rocket: The base's rocket was designed with the Tintin moon ship in mind.
- Satan: One of the many names the evil voice is supposedly known by.
- Schmuck Bait: "Don't turn around... if you look at me, you will die... I'm so close, Toby. I can touch you..."
- Sealed Evil in a Can: There is some evil creature trapped at "point zero".
- There's a lot of usage of the Doom Doors. Given that it revolves around a gigantic demon of Hell and an archaeology dig into a hostile planet going horribly wrong, it's most likely intentional.
- The idea of being kept in orbit around a black hole by a powerful artificial energy source is reminiscent of Disney's The Black Hole.
- The Doctor makes a remark that "This is gonna be the best Christmas Walford's ever had."
- Slasher Smile: Toby has these when possessed.
- Soundtrack Dissonance: A creepy, possessed Toby standing on the planet's barren surface, beckoning a woman to her death, is accompanied by a hauntingly beautiful violin.
- Speak in Unison: The possessed Ood. It's damn creepy.
- Tempting Fate: Lampshaded.
- Thrown Out the Airlock: The Beast-possessed Toby kills Scooti by telekinetically blowing out a window, causing her to be sucked outside.
- To Serve Man: Subverted. Ood surround the Doctor and Rose chanting "We must feed", but they mean to feed them, not feed on them.
- Unrealistic Black Hole:
- Black holes are black. The corona of light does not make much sense. Word of God says the original special effects were closer to reality, but they changed it to a corona of orange light to look more ominous. On the other hand, the scientist says that stuff's being pulled in. An accretion disk would have made perfect sense and given them exactly the imagery they wanted.
- They also claim there are no stable orbits around a black hole which isn't really true. Stable orbits don't exist within a distance of three times the radius of the event horizon. Unstable orbits exist even below that, down to 1.5 times the event horizon, but any disturbance (like a rocket full of humans landing on the planet) would cause the planet to drop into the black hole. As the black hole seems really close, the planet might be inside that unstable region. If we give them the benefit of the doubt and say they're inside the event horizon they might have an excuse to show anything they want. There is also the possibility that the planetoid is not in a true orbit, but that it is rather being suspended in place relative to the surface but below the geostationary altitude by whatever device is generating the gravity cone that the ship used to land. If the device were to fail, or if the planet were to shift in such a way that the gravity tether isn't facing the right way, it could cause the planetoid to fall in a black hole crossing orbit.
- Voice of the Legion: The possessed Ood, with the Beast's voice on top of their own.
- Welcome to Hell: It's written on the wall and something calling itself the devil is trapped here.
- Wham Line: "The Beast and his armies shall rise from the pit to make war against God." This is stated mid-episode by an Ood in a cheerful tone while he serves Rose her lunch. It's jarring and announces a plot different from the "space exploration" theme.
- You Are in Command Now: The ship's original captain is only seen in the TARDISode preview. He died during the flight down the "gravity funnel", leaving Zach in charge. The others assure him he's doing a good job, but he's less than thrilled. "Needs must." (Which is an abbreviated version of a very old English idiom, whose full form is "needs must when the devil drives".)