A supple leather jacket festooned with spikes. The havoc jack provides physical protection equivalent to medium armor, but counts as light armor for the purposes of encumberance. The wearer also gains a melee attack dealing 1d4 damage.
Once per day, the wearer can enter a state of violent fury (as a barbarian (or similar class) rage). If the wearer already has a rage-type ability, the duration of their ability is doubled.
The wearer has Advantage on Charisma checks to intimidate, but Disadvantage of Charisma checks involving tact or subtlety.