A white dragon scale made into a talisman, cold to the touch at all times. 

When worn, if the wearer drops to 0 hit points and fails 3 death saves, the magic inside this talisman is released, spreading a deathly chill in the area and freezing the body. The wearers body is preserved in it's dead state and it is possible to revive them as long as they are frozen. Once the body is thawed the deterioration of the body begins as usual.

While the body can be revived while frozen, the ice itself can only be melted by the fire of a gold, red, or brass dragon, by bathing the ice in flames originating from a primordial deity, or through a use of the wish spell. 

Notes: Damage: Cold, Consumable, Necklace