Stone rats were voracious rodents which lived beneath the ground in Metru Nui.
The Toa Metru once encountered a group of what looked like hundreds of thousands of stone rats in the Fikou web; their warrens had apparently been disturbed by the collapse of a tunnel. Stone rats were unpleasant creatures. Their teeth were made for eating through solid rock. In Onewa's words, "Put an Ussal cart or a chute, or even a Knowledge Tower, between them and dinner and they'll eat that, too." Since Onewa seemed to be familiar with them, they may have been present in Po-Metru. They had red eyes and made a chittering sound.
During the Visorak invasion of Metru Nui, the increased presence of ice vermin in the city led to clashes with stone rats, weakening both sides and making them easier prey for the Visorak.
Stone rats had menaced assemblers' villages in the past.
They were the preferred prey of longfangs.
Stone rats were a pest on Zakaz.
Stone rats were known to like dark and dank places.