"It was a big mistake, everything going digital and being on screens," the Doctor sighed. "Look at the Domovoi herself! That's where it all goes wrong. Now, if old Tiermann here had cut her shape out of a really big bit of cardboard... then we wouldn't be in any of this mess, would we?

BARBARA: I can’t resist it, Doctor! She is telling me what to do! I must... destroy the override controls!

DOCTOR: Nonononono, Barbara! You are your own woman! And you can make your own choices!

BARBARA: Ch-choices?

DOCTOR: Choices! You love choices, don’t you, Barbara! Of course you do! You’re a vending machine. You offer people choices all the time! That’s what you do! Crisps or pop? Milk or dark chocolate? Diet or full fat? That’s what you’re all about! Choices!

DOCTOR: When you built that monstrous Domovoi, you certainly pulled out all the stops, Ernest. You can’t kill her, can you?

TIERMANN: Nothing can do that.

MARTHA: Except the Voracious Craw. And the Domovoi knows that. That’s why she’s gone bananas.

DOCTOR: Is that a medical diagnosis, Doctor Jones?

MARTHA: Too right it is!

DOCTOR: The Voracious Craw.

MARTHA: I see.

DOCTOR: Ooooh, they’re a terrible lot. Each one is the size of a vast spaceship. They just go sailing about with their mouths hanging open, devouring things. Devouring everything they come across. They look just like, I dunno, gigantic inflated tapeworms or something. Only much worse. If your planet attracts a Voracious Craw into your orbit... well. I don’t hold out much hope. No sirree. They just go... GLLOOMMPP! And that’s the end of you. That’s the end of everything. They’re just so... voracious, you see.