Unholy Weapon

You imbue a weapon you touch with unholy power. Until the spell ends, the weapon burns with hellish flames that cast bright light in a 30-foot radius and dim light for 30 feet beyond that. In addition, weapon attacks made with it deal an extra 2d8 necrotic damage on a hit. If the weapon isn’t already a magic weapon, it becomes one for the duration.

As a bonus action on your turn, you can dismiss this spell and cause the weapon to emit a blast of unholy fire. Each creature of your choice that you can see within 30 feet of you must make a Constitution saving throw, taking 3d8 necrotic damage and 3d8 fire damage on a failed save, or half as much damage on a successful one.