A haunting remnant of the infernal realm, caught and exiled to suffer for eternity in the swamps of the mortal plane. Now it toys with mortals; luring them from their paths into it's light. Once in the boundaries of it's aura, the FlickerWikk will feed.
A Remake of the Will'o'the'Wisp/Jack'o'Lantern
Pick up a pathology/microbiology book, and add the diseases/syndroms to your game. Your players will freak out.
Coughed at? Diphteria. or tuberculosis?
Drunk from a muddy stream? Or just walked through? Well, let us introduce you to schistosomiasis...
Hit by a stream of energy? Too moch mana is ust like too much radioactivity - perhaps all mages could develop cancer early if too powerful...