You’ve possibly heard about breathtaking libraries around the world, libraries that have the most number of books, libraries that house the most illustrious books written in history, but have you ever heard about a library that possesses poisonous books? If not, then we’re here to reveal to you that the University of Southern Denmark is indeed home to a library that contains poisonous books.

The lethal discovery contains echoes of a novel-turned-movie where victims are killed off by the toxic pages of a forbidden manuscript. Sounds like a horror film, doesn’t it?

Three poisonous books were found at the library of the University of Southern Denmark. Not, mind you, books about poison. The three texts are themselves poisonous, featuring covers made with high concentrations of arsenic. The works are from the 16th and 17th centuries and cover a variety of topics.

Researchers uncovered the deadly tomes by accident. Initially, the professors X-rayed the books to try to determine whether any old Latin texts had been used in the binding.