Ruptius

It sits amid the warm rock building pressure inside its crusted body, feeding on heat and mineral, and it periodically vents the buildup in a small hiss of ash and sparks, a release it seems to find necessary and, perhaps, satisfying. Threatened, it can loose that stored pressure all at once in a sudden bursting spray of hot ash, a startling defense that buys it time to trundle away. It clusters near active vents where the heat keeps it fueled, and a slope of Ruptius all quietly hissing and venting together sounds, and smells, exactly like the restless mountain they live on.