Some form of radiated pollution had seeped deep into the rocky bottoms of the world caves, this toxic matter reached the homes of the rock dwelling Silverfish. The hazardous material caused a atom changing mutation in the cells of the Silverfish, growing and dividing additional eyes for greater perception of their environment, sharp black spikes to form on their body as a defence against predators, two large mandibles for biting prey and splitting stone, and the pigment in their blood and skin has turned a toxic green, illuminating their dark environments.