A Will O' The Wisp. They can go about on two legs and are uncanny at mimicry of human voices. Particularly cries for help. It's easy to mistake a Will (from a distance, anyway) for a small child wandering alone in the fog. They live in the swamps, where they're rarely seen, but are known for their tendency to lure the unwary to a quick and delicious death. Predictably, people hate them.

Local mythology has it that Wills were conceived when a village of Fae angered some kind of Toad god and all got transformed into half-monsters, but Wills O' The Wisp are actually mammals (though they do lay eggs). Their intelligence is unknown, though they are notorious pranksters and it wouldn't be any surprise if they turned out to be smarter than we are.