“ Stinging nettles with a deadly sting that kills within minutes if the person who is stung cannot be healed.”
“ One of the camels in the caravan trips over a dark rock protruding from the sandy dunes. The poor animal has broken its leg and cannot continue. A cacaphony ensues as the animal suffers and the caravan train overseers complain passionately as they redistribute the animal's load across the caravan. (Let's just hope none of the PC's was riding this camel, shall we?)
As the camel is put out of its misery and the camel is skewered over a campfire - waste nothing! - someone takes a minute to inspect the root cause of all the trouble. To their surprise, the upturned rock is worked stone. Some frantic digging may excavate the bottom half of a gorgeously worked1 obelisk, and maybe even the small square forum below; but a more rigorous exploration of the surrounding dunes reveals a buried tomb doorway on each side of the forum.”
“ The heroes stop in a small town ready to restock their traveling supplies and feed for their animals. All of the villagers are starving, and there is no food to be had. If the PCs are quick witted, their noble steeds might be slaughtered for food.”