From Pathfinder Adventure Path: Gatewalkers, which isn't enabled.

Cloak of Gnawing Leaves

ITEM 3

RARE INVESTED PRIMAL

Price 60 gp

Usage worn cloak

Bulk L

This cloak appears to be woven from a thousand living leaves, hungry for flesh and eager to defend the cloak's wearer.

Activate—Bite Back (concentrate)

Frequency once per day

Trigger You are damaged by a melee attack from an adjacent creature

Effect The leaves lash out at your attacker, rising up to reveal snapping jaws made of wicked thorns. The triggering creature must attempt a DC 17 Reflex saving throw.

Success The creature is unaffected.

Failure The creature takes 1d4 piercing damage.

Critical Failure The creature takes 2d4 piercing plus 1 bleed damage.

Pathfinder Adventure Path: GatewalkersORC