Burrow Grubs is the 48th chapter of Inheritance. It takes the point of view of Nasuada.
Summary[]
This chapter is the first time we hear of the Burrow Grubs. We later find out they are from the island of Vroengard in effect of the nuclear radiation. They first find the spot where they want to burrow, and then split into several centipedes before consuming the flesh. Galbatorix controls the Burrow Grubs and makes them burrow into Nasuada's elbow in a form of torture to make her swear fealty to him. Murtagh soon returns and tries to heal her vein-like scars, but to her surprise, it did not subdue the pain. Later, Eragon also comes across the strange creature on his trip to the island, where he finds that it is "not a normal creature".