Whirlwind blade

You spin around in a whirlwind of steel. Each creature within your weapons' reach must make a Dexterity saving throw. A creature takes 3d6 damage of your weapons type on a failed save, or half as much damage on a successful one.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d6 for each slot level above 1st.