For him that stealeth, or borroweth and returneth not,
this book from its owner, let it change into a serpent in
his hand and rend him.
Let him be struck with palsy, and all his members blasted.
Let him languish in pain, crying aloud for mercy, and let
there be no surcease to this agony till he sing in dissolution.
Let bookworms gnaw his entrails... and when at last he
goeth to his last punishment, let the flames fo hell consume
him for ever.
From the monastery of San Pedro, Barcelona, Spain
Kinda harsh and I don't even know what all that means but I'm okay with it.