The writer at work

BEAR: I have practiced guitar, and am about to go look for the first line of Grail in the fridge.

MOLE: Oh, is that where you keep them? I suppose it keeps them fresh.

BEAR: Well, it wasn't in the guitar.

MOLE: Are you the first line of my novel?
No, I am not the first line of your novel. I am a guitar string.

Are you the first line of my novel?
No, I am not the first line of your novel. I am a sweet potato.

Are you the first line of my novel?
No, I am not the first line of your novel. I am unidentifiab