The dragon decamped from a book about itself. Most of us had never seen a dragon, though there were dozens of books on them in the vaults. It was cute, in a smoldering sort of way, enough to make you forget, at least briefly, it was a fire-breathing lizard in a building full of paper. Of course, more alarming was how the thing arrived in the first place. Daisy Buchanan didn't crawl out of The Great Gatsby or Benedict Arnold out of A Schoolchild's Illustrated History of American Traitors. What was more, the printing within the book (Verclamps' Collected Taxonomies of the North Eurasian Microdrake) had faded and blurred and disappeared as the drake uncoiled and accustomed itself to its surroundings.
"Something else is at work here," the Professor mused. We scoured the vaults. More books were found to be empty, though we did not find the creatures they described. The Professor mused further that the drake escaped something else. Something only rumored to exist. Something which no volume, no tome could describe.
He called them silverfish, jokingly. They moved through the text of a book. They ate stories. The apex predator feasts on ideas. We studied Verclamps' tome to find any reason why the drake would have survived the process. Eventually, the Professor maintained, the ideas in texts wouldn't be enough to contain the silverfish. An outbreak would surely spread to our own hearts and minds.
He worked tirelessly at the problem. I had only been apprenticed to the Professor for a few years. When I first arrived at the Vault, and for many a month following, I found the man to be a pompous windbag. But faced with this problem, he showed his true aspect.
He created a cage book. A complete history and taxonomy of the silverfish, its language, its dimensions, culled from the distant recesses of his memory. By describing, by naming, by circumscribing the creature, he imprisoned it, finally, in a tomb of words, a prison of description.
The drake we kept as a mascot.