Jagged Vest

Wondrous item, rare (requires attunement by a character with the Unarmored Defense class ability)

This rough leather vest is covered with spiked studs, burrs, and blades. You gain a +1 bonus to AC when wearing the jagged vest and a +1 bonus on Strength (Athletics) checks made to resist being grappled or to escape from a grapple.

You gain advantage on Strength (Athletics) checks to escape from restraints such as ropes or leather cords that could be cut by the jagged vest (GM’s discretion).

In addition, the spikes and serrations of the jagged vest saw and grind whenever you are grappled or restrained. Any creature that succeeds on a Strength (Athletics) check to grapple you takes 1d4 slashing damage at the end of each of their turns that they continue grappling you.

If you have the Martial Arts class ability, the grappling creature instead takes damage equal to your Martial Arts damage die.