We’ve covered air and sea; now it’s time to tackle divine retribution on land: the thunder behemoth. At CR 18 and 25 Hit Dice, the thunder model is actually the weakest of the behemoths (fit for only destroying “a single nation or empire,” according to the Bestiary 3), but that’s likely small comfort to the cities in its path. When you're a god who needs an engine of divine destruction, but a tarrasque would be overkill, a thunder behemoth fits the bill nicely.
As with the other behemoths, I think the illustration in the B3 should be taken as an example, not a given. Your behemoths might look like Colossal xorns, six-legged lizards (à la “basic” D&D’s frost salamanders) grown to huge proportions, triple-trunked oliphaunts, a kind of styracosaurus/beetle/minotaur, or whatever. (If there was ever a time to go back and watch Digimon for inspiration, this is probably it.)
“The drow may have fallen,” it is sometimes said, “but ’twas tower elves that gave them a push.” Ever since then, no tower elf (see the Advanced Race Guide) civilization has been allowed to take root. While they may inhabit other elven cities as they please, any time they gather in numbers too great or see one of their number crowned, a thunder behemoth inevitably erupts from the earth to ensure their namesake crystal spires fall.
Crafting a sword powerful enough to slay a deity’s son was reason enough to punish the Vault of Dolbaddon for their hubris with a thunder behemoth. And that sword, so desperately needed by adventurers now, is still in one of the behemoth’s five stomachs, encysted where it lodged after being swallowed so long ago. The behemoth itself has not been seen for a millennium, and is presumed buried deep in the mantle or on another planet entirely.
The Lashkalan Jungle is impenetrable even for skyships—storms cycle through the rainforest year-round, and the trees have been witnessed shooting vines and cannonball-hard seedpods whole cable lengths into the air to bring down flyers. The one sure path through the jungle is to follow the meandering route of the Ravening That Walks, a tempest behemoth that devours all before it. Of course, the bristling, pangolin-like dinosaur has been known to double back on its own trail from time to time…
—Pathfinder Bestiary 3 39
Edit: Sorry for the lateness of this post. I know some of you have been awaiting it eagerly. Original entry: Busy with Thanksgiving. Post to come tomorrow. Gobble, gobble!