Swords of Fire

You create 3 flaming swords in your space. They float in the air behind you for the spell’s duration. As you cast the spell, and as a bonus action on your later turns — you can expend one of the swords, sending them soaring through the air toward a point you choose within 100 feet of you. Once the sword reaches its destination or impacts against a solid surface, the sword explodes. Each creature within 10 feet of the point where the sword explodes must make a Dexterity saving throw. A creature takes 3d6 fire damage on a failed save, or half as much damage on a successful one.

When you cast this spell using a spell slot of 5th level or higher, the number of swords created increases by three for each slot level above 4rd.