Cats are known for many things, and among these things is the fact that sometimes they pee on things. Now there's a whole lot of reasons for why a cat might pee on something - it smelled like pee before, the cat is stressed, the cat is in pain... but whatever the reason - the result is cat piss on something.
And that something might even be a manuscript. Which they might also not use as a perfect place to piss, but just walk over it.
Go follow this link to see for yourself. Me? I'll be checking on the cat now. Maybe she wants a book.