Thorns

Thorns is an armor enchantment that causes attackers to be damaged when they deal damage to the wearer.

Usage
This enchantment has a  chance of inflicting damage, with a maximum of 100% Chance. If thorns does deal damage, it will deal - (or  if Level > 10) damage on anyone who attacks the wearer, whether by melee attack, arrow, or other projectile.

Thorns applies a durability penalty to the armor. It reduces durability by an additional 3 points when inflicting damage. If multiple armor pieces are enchanted with Thorns, then each piece separately inflicts damage on the attacker, and the Thorns durability penalties are applied to each piece individually.

Obtaining
Thorns I and II can be obtained naturally from drops or by combining the enchantment from a book. Thorns III can be obtained only by using an anvil to combine two Thorns II enchantments, or by combining the enchantment from a book obtained via trading with a villager.

Thorns can be applied to a non-armor item only by using commands or a third-party tool. When such an item is held in either hand, an attacker suffers damage according to the formula above but with no durability penalty.

Video
荆棘