“ A new substance is found in an out of the way area and kept very quiet. It is found to make a perfect counterfeit diamond. Only the most expert of expert appraisers would even have a hope of noticing that it is fake. Only one problem: if it gets wet it starts to slime and if it is saturated, it turns into a glob of gel.”
“ If you want to add a 'supernatural' touch to your campaign, define the rules of magic and the universe. Make your players comfortable with those rules. Then your new supernatural creatures must then break those rules.”