From Pathfinder #156: The Apocalypse Prophet, which isn't enabled.

Guthallath Rockslide

COMPLEX HAZARD 19

Stealth +30 (master) to notice the odd aging of the stones, seemingly far older and more weathered than the surrounding rocks

Description The rock walls nearby begin to crumble and collapse.

Disable DC 48 Crafting (legendary) to buttress the collapsing rocks in three different locations. Using large and durable materials (or applicable spells) to support the rocks reduces the check to DC 45 Crafting (master).

AC 42; Fort +35, Ref +29

Hardness 20, HP 150 (BT 75) Hardness 10 in the guthallath's erosion aura; Immunities critical hits, precision

Rumbling Rocks

Trigger The guthallath rolls initiative

Effect The rocks of the area begin to crumble. The hazard rolls for initiative.

Early Collapse

Trigger The hazard takes 30 or more damage

Effect Move the hazard's initiative to immediately follow the creature that damaged the hazard.

Melee Falling Rocks +36, Damage 4d10+20 bludgeoning

Routine

(2 actions) On the hazard's first action, any areas of crumbling rocks from a previous round collapse, making a falling rocks Strike against each creature in the area.

On its second action, the hazard crumbles rocks in a 20-foot radius around the previous collapse. A character can Seek (DC 40) to determine where the rocks will fall on the following round, but on a critical failure, they incorrectly identify where the rocks will fall.

Reset The guthallath can reset the hazard with a few days of work stacking the fallen rocks.

Pathfinder #156: The Apocalypse ProphetOGL