A creature that lurks behind stacks and in between shelves. It will commonly devour small children. Sometimes the monster will reorder books from its favorite to its least favorite rather than adhering to the dewey decimal system. The library monster's greatest foe is the librarian. They are born when a creeper lurks in the shelves for too long and eventually becomes a library monster.

(noun) A successful type of theft which results in an acceptable, impressive and rewarding payday for the protagonist.