Armor of Kelemvor

Once per day you may squeeze the bag over your head. A
magical force surrounds you as the slime expands to
cover your body. Make a constitution saving throw. On a
DC10 you gain 1d10 + 5 temporary hitpoints for the
duration. If a creature hits you with a melee attack while
you have these hitpoints, the creature takes 1d10 necrotic
damage. If you fail the constitution saving throw, you
cannot handle the slimy feel of it coating you and the
whispering of the dead inside your mind, take 1d10
slashing damage as you attempt to claw it off.