Blood Lightning

You cast this spell on a willing creature. The next time that creature takes damage from a melee attack a bolts of crimson lightning explode from the wound. Each creature within 20 feet of the target of this spell must make a Dexterity saving throw. They take 8d6 lightning damage on a failed save, or half as much on a successful one. At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d6 for each level above 4th