Nano-bug

The nano-bugs eat everything that is organic and when they are done and the planet is non-organic they starve and go for a long sleep. They are the true emperors of this god-forsaken planet. Nobody knows what wakes them up. In fact there is nobody to know them right now. Knowing is something that belongs to complex organic creatures which are yet to evolve from the inorganic life forms - again. Nobody knows (again) how these nano-bugs operate, only that everything reduces to basic molecules like amino acids and sulphates.