Eldritch Fireball

A bright streak flashes from your pointing finger to a point you choose within range and then blossoms with a low roar into an explosion of death. Each creature in a 20-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes 8d6 necrotic damage on a failed save, or half as much damage on a successful one.

if a creature is killed by the spell. the creature must make a Wisdom saving throw or become a Skeleton.

At Higher Levels. When you cast this spell using a spell slot of 7th level or higher, the damage increases by 1d6 for each slot level above 6th.