“ Pick up a pathology/microbiology book, and add the diseases/syndroms to your game. Your players will freak out.
Coughed at? Diphteria. or tuberculosis?
Drunk from a muddy stream? Or just walked through? Well, let us introduce you to schistosomiasis...
Hit by a stream of energy? Too moch mana is ust like too much radioactivity - perhaps all mages could develop cancer early if too powerful...”
“ The players see a small shrine to the local nature deity just of the trail. Before they even approach it, they can smell the foul stench of rotting meat. If they inspect the shrine, they can see it has been desecrated by rotting organs in the last few days. There is no mistaking it for an obscure ritual, the organs are thrown everywhere, not left in specific places as in sacrifice.
If the players try to clean the shrine, they will soon find it has been boobytrapped to fling sharp splinters covered in the rotting gore in every direction. While only doing a few points of damage, they injured players will likely take sick soon unless they get medical attention.”
“ The Pcs discover an ancient, dusty oil lamp, somewhere in the bowels of a dungeon. Naturally they 'rub it', and out pops a wizened, old djinn. So far so good. Then it speaks...
'Ah at last, at last I am free! Now grant me my wish!'
When the PCs explain that they are the ones that should be granted a wish, the malignant djinn explains to them that his particular oil-lamp has a curse placed upon it. Whomsoever releases the entity inside shall be geased to grant the djinn's wish to the best of their ability.
Groans ensue from the party. The djinn rubs his wrinkled hands, grins, and proceeds to name his wish. What could it be?”