Unstable energy coalesces around you, coating your skin with gossamer silver energy. This energy then explodes in a 15ft. radius sphere around you, dealing 2d8 Necrotic damage and 2d8 Force damage to each creature in the area other than yourself. Each creature in range must make a Constitution saving throw; on a success, the creature takes half damage from the explosion. Following the explosion, you regain 1d8 HP as the energy lingers on each creature and slowly siphons the life from them. Starting on your next turn, for the spell's duration or until you lose concentration, you may use your bonus action to reactivate the bomb, dealing only the Necrotic damage and still regaining HP.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, gain an additional 1d8 to both damage and healing amount.