The gnawing lurker is a species of lurker encountered at Spider Cave during The Precursor Legacy. They are found throughout the cave gnawing on wooden support beams. Jak and Daxter are tasked with eliminating them in the mission "Use your goggles to shoot the gnawing lurkers", after which they receive a power cell.
Gnawing lurkers bear the resemblance of massive centipedes. They are red in color, have large legs, and traits common to all species of lurker such as yellow eyes, a metal collar, and spurs placed along their jawline. It is unknown why they were gnawing on the support beams, though it is likely they were searching for some type of Precursor artifacts under the control of dark twins Gol Acheron and Maia Acheron, as many other lurkers were throughout the course of the game. As they are defeated, they drop Precursor orbs, which could indicate they were looking for and capturing orbs.
Gnawing lurkers will not attack you, and will scatter into the burrows of their beam any time you get within their range. Instead, the only way to defeat these lurkers is to use the yellow eco vents placed around the cave and shoot them. This can be accomplished by standing on a vent, pressing to use Jak's goggles, and then pressing to shoot yellow eco projectiles at the lurkers. Be careful, as the lurkers will still retreat when they see the yellow eco coming towards them, and are additionally very fast, presenting a challenge in destroying them quickly and accurately.