Berserker Armor (3.5e Equipment)
From D&D Wiki
Berserker Armor: This +3 fearsome banded mail is truly a sight to behold. When worn by a barbarian, it becomes even more potent. A barbarian wearing this armor can rage indefinitely, but cannot end their rage voluntarily without making a DC 16 will save. The berserker armor also grants its wearer obscene endurance; a barbarian wearing this armor cannot be slain by massive damage, reducing their health to -10 or less, or by instant death effects (other than disintegration). However, should the wearer be beyond -10 health, they cannot remove the armor voluntarily or else they will die immediately. Once per month, the wearer who has -1 or less health may raise their health to 0, allowing them to keep fighting or otherwise remove the armor without harm.
Strong enchantment;CL 16th; Craft Magic Arms and Armor; rage, death ward; Cost 50,275 gp + 800 exp; Weight: 35 lbs lb.; Market Price: 100,550 gp