Amulet of The Run

Once worn by an incredibly skilled gambler. the amulet is said to have the furious soul of such an incredibly lucky man trapped inside it. once every long rest, if an ally you can see within 60 ft of you will die from an attack, you may use the amulet to temporarily negate all damage for a round of combat to whomever is going to die. but if you try to use it again there is a 30% chance that the amulet won't work. And if you decide that you're gonna use it a third time, the soul in the amulet will get angry at your overuse of its power, and you must roll a dc 16 con save as to not be damaged for half your remaining health. using it a fourth time has a 90% chance to break the amulet.