Avatar: The Last Airbender, Book 1: Water

Koh:
My old friend, the Avatar. It's been a long time.

Aang:
You...know me?

Koh:
Oh, how could I ever forget you? [Changes face to that of an angry-looking man.] ONE OF YOUR PREVIOUS INCARNATIONS TRIED TO SLAY ME! It was eight or nine-hundred years ago.

Aang:
I didn't know that. Why did he...or I...try to kill you?

Koh:
[Changes face to that of Ummi, Avatar Kuruk's wife.] Oh, it was something about stealing the face of someone you loved. [Changes face to that of a screaming baboon in an attempt to scare Aang.] HA HA HA! [It doesn't work and Koh keeps talking, bringing his fanged maw right up behind Aang's ear. ] Of course, that's all behind us. Why should I hold a grudge against you for something in a past life? After all, you're a different person now. You've come to me... with a new face.