Have you ever left a book for one minute, and returned to find it back on the shelf?  Page markers on the wrong pages, or missing altogether? How about a book you borrowed only yesterday being mysteriously overdue?

Conjured inadvertently by the careless thoughts of daydreaming librarians, this growing brood of mischievous dragons spend their time wreaking havoc in magical libraries.

Never causing any real damage, these creatures are rarely glimpsed by human eye, and never by the library's keeper, for when he wakes, the Bookwyrms sleep.