Just imagine a powder, that could make thing eatable (like swords or rocks).Try it an it will be verry funny.Just imagine..characters will need to get some information from someone. And if he will saw, as one PC is eating his sword.
Consider the idea of spontaneous genesis of life, as used to be belived. What strange kinds of life might arise from modern substances? What kind of vermin would a landfill produce, or an oil spill on the ocean?