Ancient God Script (Rebirth)

By some means you managed to learn the magical circle of the Ancient God Script (Rebirth). whether that be through a magic item that has the spell inscribed on it or from a Spellbook or shire force of will. 

Upon dropping to 0 hit points you can use a reaction to cast Ancient God Script (Rebirth). A 60-ft radius magic circle immediately appears beneath you crackling with the energy of your magic. All creatures within the circle take necrotic damage equal to your class level. If the amount of damage delt is equal to or exceeds your maximum hit points you are resurrected the at full health after 24 hours. 

Alternatively you can enchant an item with this circle. Doing this allows the enchanter to apply the main affect (Rebirth) to the wearer or wielder of the item. Another benefit of enchanting is the ability to modify the Spell Potency, Spell Activation, Circle Size, and Spell Duration parameters with Modifier Circles.