Vauban's Ball of Misty Rings

Your body manages to concentrate your wild magic, unleashing it in the form of a green and black 20ft-radius-sphere of mist, in which yourself and 4 creatures of your choosing are healed, while hostile creatures are harmed. Upon cast, you and the 4 chosen creatures are healed for 2d10 hit points, while hostile creatures take the same amount as necrotic damage. For each turn they begin in the sphere, the 4 creatures will heal for 1d10 hit points, and hostile creatures will take the 1d10 necrotic damage, calculated individually.