Swarm Blast

You cover a projectile weapon with parasitic bugs and fling it at one creature within range. Make a ranged spell attack against the target. On a hit, the target takes damage equal to the thrown weapon's standard damage. Hit or miss, the bugs spread. The target and each creature within 5 feet of it must succeed on a Dexterity saving throw or take 2d6 necrotic damage.

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