Bookworm

You can just taste the author's depression!

Bookworms is the collective name given to the larva/nymphs of many species of insects, from cockroaches, beetles, flies, and ants that feed foremost on the binding and glues that hold books together rather than the paper of the books themselves, only going through the paper to get to the binding. But in typical human fashion bookworms have become both creatures of semi-mythical status and as a phrase for someone who constantly has their nose in them.

Dungeons & Dragons

Appearing in the Forgotten Realms, bookworms are thick maggot-like worms that are the #1 enemy of magic users besides the usual suspects. They love to eat paper, especially those inscribed with magic such as runes, spells, hexes, and enchantments. They'll also eat leather as quickly as they do paper. They don't attack living things, however, so don't worry about Rot Grub type shenanigans. They do possess an impressive 8 ft leap to escape from danger.

Pathfinder

Much the same as their original DnD counterparts, however, they are much more voracious for spells, are now able to leap 20 ft, and can change their color to hide.