Death's Blade

You brandish the weapon used in the spell’s casting and make a melee attack with it against one creature within 5 feet of you. On a hit, the target suffers the weapon attack’s normal effects, and you can cause black flames to engulf the target for 1d4 necrotic damage. Or you can do base weapon damage to your target on a hit and send a coil of flame to a secondary target within 5 feet for 1d4 necrotic damage.

This spell’s damage increases when you reach certain levels. At 5th level, the melee attack deals an extra 1d4 necrotic damage (2d4 to the target) or 2d4 + your spellcasting ability modifier to the second creature. Both damage rolls increase by 1d4 at 11th level (3d4 and 3d4) and 17th level (4d4 and 4d4).