Will-o-the-wisps

Will o' the Wisps are sprites who have a mischievous or malevolent nature, taking the form of a light, and luring unwary travelers into dangerous situations, then blinking out, leaving people stuck in bogs or on cliffs, far from home and in the dark. The name Will-o'-the-wisp has an etymology of "William of the wisp [of lighted straw]". They do not seem to be related to the demi-fey.