You're going to be doing some lines for me, Mr. Potter. No...
Dolores Umbridge: [Harry has come in to do his detention] You're going to be doing some lines for me, Mr. Potter.
[Potter opens his bag for his quill but Umbridge stops him]
Dolores Umbridge: No, not with your quill. You're going to be using a rather special one of mine. Now, I want you to write "I must not tell lies."
Harry Potter: How many times?
Dolores Umbridge: Let's see... As long as it takes for the message to sink in.
Harry Potter: You haven't given me any ink.
Dolores Umbridge: Oh, you won't need any ink.