Exotic Encounters: Will-o'-Wisps
The Pathfinder Bestiary, and the long line of monstrous encyclopedia that came before it, do a great job of attacking the problem of providing game statistics and mechanical information for a very wide variety of creatures. There are a lot of strange creatures from fantasy novels and movies, from ancient mythology, and, as time went on, from the twisted minds of game designers and even GMs, for that matter. Anyone today who tried to go about creating an extensive bestiary of all the different cool and interesting fantasy monsters could fill three or four volumes with three hundred monsters each, and still have a long way left to go, with fans crying out for various "forgotten" monsters to get some attention. That kind of breadth doesn't leave a whole lot of room for depth, and that's where Exotic Encounters comes in.
There are all kinds of reasons why you might not want to use a monster stat-block straight from the core rules. For one thing, if your players have a habit of browsing through such books, or are long-time veterans who know the basic ins and outs of most fantasy staples, you may need an unusual stat-block just to throw them a curve ball and teach them that they can't count on their out of character knowledge to take all the mystery out of the game. Alternatively, many GMs can recall a time when they wanted to make use of a certain monster in their game, only to find that it was a few CRs too high or low for what they had in mind.
Exotic Encounters takes a single, iconic monster, and creates three new variants on that theme. These variants aren't simple tweaks, and are more than simply advancing or removing Hit Dice, though that occurs as well. Each of these three variations on the monster's theme has a specific, flavorful goal in mind, and a role to play, and their statistics entries are gently massaged in order to make them fit those roles. Further, each of these variants comes with brand new specially-crafted special abilities, which are unique to Exotic Encounters and not found anywhere else.
This particular installment of Exotic Encounters focuses on will-o'-wisps. While these mysterious creatures of the swamplands are mostly known for their tendency to lead victims on wild goose chases into dangerous situations, the fact of the matter is that Pathfinder will-o'-wisps are built more for mobile beaters with ridiculously high attack, damage, AC, and maneuverability (plus constant invisibility) than they are for being elusive or tricky. While all of these will-o'-wisps can certainly hold their own in a fight, we aimed to capture a bit more of the essence of the wisp. The first result was the wispling (CR 2), a smaller, weaker version of the will-o'-wisp that can instill fear on opponents with its unnerving touch and ghostly lights abilities, and then bask in that fear with their feast on fear ability. The next new will-o'-wisp is the dark guide will-o'-wisp (CR 9), whose guidelights ability compels those who see it to follow it, regardless of where it takes them. These corrupted will-o'-wisps feed on death, more than fear, and lead travelers to early graves in order to sup on their last breaths. Finally, the devil's eye will-o'-wisp (CR 13) appears at first to be a simple cloud of illuminated marsh gas, but, in fact, has numerous powers, including its maddening witchlight and its terrifying ability to split into multiple creatures.