From Pathfinder Society Scenario #1-01: The Absalom Initiation, which isn't enabled.

Collapsing Floor

HAZARD 2

Stealth +4

Description Around the edges of the pit, more rotting boards are ready to give way.

Disable DC 16 Crafting to reinforce the beams

Pitfall

Trigger A creature walks next to the pit.

Effect The triggering creature falls in and takes falling damage (typically 3 bludgeoning damage) plus 4d6 piercing damage from landing on broken boards.

That creature can attempt to Grab an Edge to avoid falling; the DC to Climb the walls or Grab an Edge is 18.

Reset As the damage to the floor spreads, the areas adjacent to the new pit become new areas of this hazard.

Pathfinder Society Scenario #1-01: The Absalom InitiationOGL