Dr who tenth doctor quotes Turn Left

Donna: I'm nothing special.
The Doctor: Yes you are, you're brilliant. 
Donna: She said that.
The Doctor:Who did?
Donna: That woman. I can't remember.
The Doctor: She never existed now.
Donna: No, but she said, the stars, she said the stars are going out.
The Doctor: Yeah, but that world's gone.
Donna: No, but she said it was all worlds, every world. She said the darkness is coming, even here.
The Doctor: Who was she?
Donna: I don't know.
The Doctor: What did she look like?
Donna: She was... blonde.
The Doctor:What was her name?
Donna: I don't know.
The Doctor: Donna, what was her name?
Donna: But she told me, to warn you. She said two words...
The Doctor: What two words? What were they? What did she say?
Donna: Bad Wolf. W-What does it mean?
Donna: Doctor, what is it, what's Bad Wolf?
The Doctor: It's the end of the universe!