Corrupted Bolt

You create a bolt of discolored lightning and throw it toward a creature within range. The creature must succeed on a Dexterity saving throw or take 5d8 lightning damage as well as 5d8 necrotic damage and have its hit point maximum reduced to its current hit point total after it has taken the damage from this spell. If this would cause the creature's hit point maximum to become zero the creature dies. A creature can make a Constitution saving throw at the end of each of its turns returning its hit point maximum to its original value on a success. On a successful save the creature takes half as much damage and its hit point maximum is unaffected.