Expiration

The blackish purple flames of the Fell Dragon gather in your hands, which you launch, making a ranged spell attack against an enemy within 60 ft. of you. On a successful hit, it deals 4d6 points of necrotic damage. If the foe hit by this spell has resistance to necrotic damage, it is instead treated as though it does not, and likewise if the foe is immune to necrotic damage, the damage is halved instead.

At Higher Levels. If you use this spell using a spell slot of 4th level or higher, the damage is increased by 1d6 for every slot level above 3rd.