Gredbyg (singular: Grodbog) are a breed of large insects found in the depths of Moria. Grodbog hatchlings resemble beetles or pill bugs. They are small and usually not aggressive unless provoked. The full-grown gredbyg, however, are larger, mantis-like, and covered in a chitinous exoskeleton. They will aggressively attack adventurers that they perceive as a threat to the hive. In the Dwarves' absence, the gredbyg overran the tunnels of Moria and are now proving to be a danger to the Iron Garrison attempting to reclaim Khazad-dum. During the War of the Ring, the gredbyg have begun to spread to other regions as well, such as the Great River and the Under-wall tunnels of Rohan.
A list of all known sightings: