The PCs come across a pyramid or some other type of tomb, containing-if they chose to break open the seals and enter it, some ornate and very valuable tomb treasures-and unfortunately one or more Bandage Beasts. They can be held off or indeed defeated using water, but the treasures of the tomb will be of no use to the PCs if they die of thirst in the desert before reaching civilisation again.
A huge scorpion the size of a horse, the apex predator in this area, arrives and attacks at once with it's armoured pincers and that fatal sting on the end of it's tail. If the PCs defeat it, armour can be made from it's body, and that deadly tail can be made into a nasty poisoned sword. These scorpions tend to live on the edge of deserts rather then in the centre of them, as there is more prey to be found that way for such a large creature to eat.
An underground source of water has soaked the sand above and turned it into quicksand. Assuming the PCs are not dragged down and killed by it, straining the sand properly yields drinkable fresh water-something very precious and life sustaining in a desert.
A trading caravan shows up with about a hundred traders, all of them armed against the danger of desert raiders. If the PCs are friendly and have money, interesting items to trade or both, they will happily trade in return and are reasonably honest. If the PCs get aggressive and/or try to attack them, they will fight back, and there are a lot of them who are not in a forgiving mood.
A dozen or so hooded raiders on fast camels show up and attack the PCs on sight. If the PCs survive the encounter they get the swords and whatever else the raiders have. If they wear their clothing, non raiders will either flee in fear or become very hostile
The PCs find an oasis with a whole community of desert dwellers living there. Access to the water is free but tightly controlled to prevent it being fouled or worse, poisoned. The PCs if they know where to look can find traders, information and somewhere safe to sleep here. If they get in a fight and win it, they will be persona non grata unless they can prove that they didn't start it.
The soldiers came in large numbers and heavily armed, and to get at the water quickly they blew it up. There was nothing the outnumbered oasis dwellers could do. The water flooded out and formed a huge pool. When the soldiers had drank their fill, filled their canteens and moved out, the oasis dwellers drank and gathered the water whilst it was still fresh. After a couple of weeks of sitting on the surface the water became foul, the water table dropped and killed the date palms, mosquitos arrived bringing malaria with them, and the oasis dwellers had no choice but to flee and hope to be accepted at some other oasis. Now the water has to be boiled to make it drinkable, otherwise it causes sickness and dehydration, and malaria is a danger to anyone who stays here very long.
Additional Ideas (1)
8) The False Prophet:
Martell, our guide, inclined his head slightly towards the lumbering figure that was stagger along the road toward us.
“Sis is no correct. Dat mon is an etranger. Moi desert, she will not care for his kind.”
The PCs encounter either a campsite or a heavily burdened figure walking alone along the desert road. This figure is a young man in his late teens or early twenties. He is well prepared in terms of his equipment, but there is something off about him. His clothes are garish. His supplies are new but poorly maintained. His eyes are frightened, his skin is pale or freshly sunburnt, he is physically weak and overburdened. He is not from this desert and he is not use to hard labor.
This young man heard of prophecies about a messiah type figure that will come out of this desert. He became to believe that he was this prophet, and he left his relatively easy life to venture into the desert. But the desert is harder and more pitiless than he thought. He has had no epiphanies and his vision of how this would go has not matched the realties of his experiences. He is a soft man who wants help and reassurances. If the PCs show him any kindness he will latch onto them. Despite his pride, he possess an overwhelming need. He will want two things from the PCs: some one to care for him/help him and two he will look for some sort of affirmation or conclusion. As much as he wants someone to guide him out this waterless hellhole, part of him is still hoping that these PCs will help him become the import person that he deeply wants to be. Are they sign he has
RPing: If your PCs are like most game parties they are in this desert for some violent and/or dangerous purpose. This guy will be a burden. Also, while he has been humbled by his experience, he is still extremely self-centered. He will try to engage the PCs in long conversations about his life and look for them to tell him it is okay. He will not pick up on cues or hints. He will eat up supplies and game table time that could be spent fighting giant monsters. How will the PC deal with this sad but not entirely sympathetic character? Will they derail their own plans to help him? Will they allow him to slow them down? Or will they scrape him off their boots? Whatever choice they make could come back to haunt them in the future.