Able to see in pitch darkness and sense vibrations through their large flat feet, cave trolls often lie in wait in narrow tunnels they have excavated, ready to pounce on anything that may happen by. Alternatively, they may take a more active approach, sensing prey through a dividing rock wall and putting their powerful arms and claws to work to spring an ambush. A cave troll has no fear of tunnel collapse or of natural predators; it can will its already tough skin to become as hard and impenetrable as rock for a short time.