Exotic Encounters: Froghemoths
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 the froghemoth. These strange creatures seem like they would be more at home in a sci-fi pulp setting than the average fantasy game, and this is played up in their entry in the Pathfinder Bestiary, which teases of an alien origin. This book imagines three varieties of froghemoths that might have developed on other planets in other conditions, which can serve a fantasy campaign just as well as the original, or make for an exciting encounter should your players choose to venture beyond the stars. First is the arctic froghemoth (CR 8), the product of a frozen world, its tentacles end in barbed harpoons, and its icy breath slows those affected by it. Next is the volcanic froghemoth (CR 16), which prefers a warmer clime, and can spit globules of burning pitch that remain on the battlefield and serve as a dangerous obstacle, and which possesses a dangerous fire aura that helps protect it from its crippling weakness to cold. Finally, the deep froghemoth (CR 19) may well be the last remnant of an ancient space-faring race of proto-froghemoths who populated the stars. In addition to being more intelligent than its kin, it is much larger, with a body that sweats acid and the ability to surround itself in a cloud of deadly spores.