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?
A demon who isn't some hideous creature bent on consuming souls, bu is, in fact, a likable chap who enjoys having pleasant chats with people - trying to talk them into becoming his servants.
Small village tavern specialty of the house is fresh cow blood mixed with milk. For each order they go out back and actually draw blood from a cow by puncturing a vein in it's neck. Fresh blood brought to the table where they poor milk into the glass of blood in front of the customer so they know how much blood they are getting.