Human: Compose a short description of a foreboding setting outside a wilderness cave with unsteady ground. a noxious, sulphurous odor clings to the air, threatening to overwhelm the senses. Assistant: 
A noxious, sulphurous odor clings to the air, threatening to overwhelm the senses. Yellow-green pockets of the gas linger near the pit, though exactly what they are or where they come from is unclear. Falling away into the abyss is a length of rope with rusty red discolorations marring the frayed knots that secure it topside.