Would it be possible to create a potion which flags the player as essential but only for one death.

Simply put the potion would heal the player by an arbitrary amount when the players health reaches zero. After this occurs the next time the players health is reduced to zero they die.

Another idea would be an item ( amulet or ring ) that would produce the same effect rendering the item useless after the cheat death mechanic has triggered.

These items could be extremely rare and finite in number.

Is something ike this even possible?