From Pathfinder Society Scenario #1-12: The Burden of Envy, which isn't enabled.

Submerged Shard

HAZARD 1

ENVIRONMENTAL

Stealth +8 (trained)

Description An immense, jagged piece of clear crystal 10 feet square and forty feet high juts up from the seafloor

Disable DC 13 Survival (trained) to blunt the crystal's edges without getting cut

AC 16; Fort +10, Ref +4

Hardness 7, HP 24 (BT 12); Immunities precision, critical hits

Shard (attack)

Trigger A creature or object moves into the shard's space.

Effect The triggering creature takes 2d6+5 piercing damage (DC 17 basic Reflex save).

Reset The hazard still damages any creature or object that enters its space, but the surface doesn't become hidden again until it settles over the course of 1 minute.

Pathfinder Society Scenario #1-12: The Burden of EnvyOGL