“ A Deity of some sort has unleashed a plague of bookworms or something like that in the area. Almost all spellbooks are destroyed, along with bardic and historical books.”
“ If thrown into a moat or a ditch, they react with water to make an area of ground a foot wide and solid enough to walk on rise from the bottom. If eaten-well, the body of the one who ate one of them is a real mess. Used to storm moats and forge rivers, streams and ditches. Must be kept dry until used.”