From Pathfinder Rage of Elements, which isn't enabled.

Brine Dragon Scale

ITEM 8

UNCOMMON ACID CONSUMABLE TALISMAN WATER

Price 100 gp

Usage affixed to melee weapon

Bulk —

Usage affixed to a melee weapon

Activate (concentrate)

Prerequisites You're an expert with the affixed weapon

Trigger A creature in reach of the weapon takes an action with the concentrate trait.

Brine dragons are known to distract their foes at just the right moment, and this blue-green scale appears to have come from one of these creatures. When you activate the scale, it cracks open and releases a spray of caustic saltwater at the triggering creature. The creature takes 2d8 acid damage with a DC 24 basic Reflex save. If the creature critically fails at its save, its concentration is broken—the triggering action is disrupted.

Pathfinder Rage of ElementsOGL