Two creatures, forever cycling between the phases of the 5 elements, unable to rejoin.
The unnatural offspring of a zombie father and a human mother.
The excited, almost frantic sound of a mallet instrument erupts from the forest to your left. Within minutes, your party is confronted by a host of short, sprite-like gnomes clad in vivid greens and earthy browns. Attempts to communicate fall flat. The gnomes seem to ignore your words entirely, and you cannot understand the humming/whistling/snapping that apparently makes up their language. Luckily for you and your fellows, however, they don't seem hostile . . .
You find a patch of edible funghi. They taste well and all, no ill effects. UNLESS you consume some beverage, even 3 (three) days after eating it. Then you become really sick with pains, vomiting, all the fancy stuff. As a gift or good meal, it could be a cruel joke or to make sure the heroes spend their time focused on the mission. And the fine soup you had in the inn yesterday could have some in.
(Inspired through a real-world fungus. Was really used to cure alcoholism.)