Event on Colossal Cavern

The acrid smell of boiling tar permeates the air. Overhead, misshapen birds barely manage to flap by, oil dripping from their batlike wings. "Pterodactls!", cries Margo the Mapmaker, "Haven't been seen in Skara Brae since the great cleansing sixty years ago. Probably means other critters are back, too. Better watch where you step."