Froghemoth

There is pretty much no going around it: The froghemoth is not of this world, or at least not of any ecosystem most characters would be familiar with.  It’s strongly suggested in most published appearances that they are actually alien creatures.  They might also be aspects of divine rage, primeval menaces from out of time, or the result of truly reality-bending experiments.  Accordingly, there is no casual or random deployment of a froghemoth in an adventure arc.  It should always be the penultimate or final encounter—and a springboard into the next arc…namely, “Where did that thing come from, and/or who sent it?”

The metal sky canister the boggards have unearthed holds the jelly cocoon sack of some Huge froglike creature.  The boggards believe it is a mobogo sent by their demon god to lead them.  The swamp’s vooniths could tell them otherwise, but they fled the area at the first sight of the canister—almost as if they knew what it contained…

This is true: The world is hollow.  This is also true: It is larger inside than out.  No divination spell will reveal these things, nor any divine emissary.  Only by witnessing this land with your own eyes may you learn of it.  Dotting this inner realm are strange vibrating spires—the source of the magical interference and a potent conduit for bardic magic.  Many of the spires are guarded by froghemoths. Others stand unattended, their croaking former servants wandering half-mad as they prey on dinosaurs and civilizations alike.

A tattered scroll declares that the First Apocalypse will be heralded by two signs: “The Servants of the Horseman of Pestilence do thus ride out, and o’er the Land a Plague of Frogs.”  Now, as leukodaemons manifest in droves, a party of adventurers discovers the second half of the prophecy was rather poorly translated…

—Pathfinder Bestiary 136

port·man·teau  /pôrtˈmantō/  n.  1. A large trunk or suitcase opening into two equal parts.  2. The thing from the Barrier Peaks that just ate your character.