CR 1/10

This small worm, only one inch long, is greatly feared by mages because it is attracted to paper in all forms. Bookworms inhabit libraries, eating through the pages and bindings found there. They cannot eat living matter, but they will burrow through dead wood, leather, and other normal book materials at a surprising rate. They are very fast (movement 20 ft per round) and seek to avoid capture and combat when discovered. Normally a dull gray color, a bookworm's chameleon-like abilities enable it to instinctively blend into any background (Spot check at DC 20 to notice).

   When an adventurer is careless enough to encounter a new brood of bookworm larvae, he can inflict incredible damage by carrying them unwittingly with him to other places. A handful of larvae hiding in a backpack traveling down a city street can find new homes readily, destroying the libraries of sages, temples, wizards, and governments in the process.
   A bookworm brood will consist of 20-40 worms. Each bookworm deals 3 points of damage to dead wood, rope, paper, or leather each round it spends burrowing. A bookworm cannot harm living matter, or any substance harder than dead wood or leather. It destroys spellbooks and scrolls at the rate of one spell level per round (i.e., five rounds for a scroll with a single 5th-level spell).

   Any physical or magical attack kills a number of bookworms equal to the damage dealt.

The Bookworm first appeared in the 1e MM II (Gary Gygax, 1983).