Prank Book

Hey Twilight, do you have any books about pranks?

Oh, no. I'm not letting you get away with it this time.

You don't have one?

I do, but I'm not letting you check one out just so you can prank me. I'm on to your little scheme.

But Twilight, if you don't loan out books to ponies who ask, aren't you failing as a librarian?

Well, that's, um, that's true, but, uh...

So how about that book?

...Fine. Here it is.

I don't even want it any more! April Fools!

That's not even a prank!

Isn't it? Maybe you should check the book.

Fine. Look, see? It...

it says...

Yes?

It says "Psyche" on every single page.

Gotcha!

How did you do that?