As you once were bitten by the thorns, the thorns now bite for you
When in danger your coat or jacket can sprout crossed layers of thorns, creating a thick armor around your upper body, your head if you are wearing a hood, or anywhere the article may cover. In even greater moments of desperation, it can form a loose wall of them extending from your forearm, creating almost a tower shield of brambles.
You have 3 Armor, which reduces incoming Damage. Armor from multiple sources does not stack. Passive, always in effect.