Triton' Arcane burst

A glowing arcane ball forms in your hand and with a swift throw you make it fly to a point you choose within range and then explodes with a low thud in a 20-foot radius sphere of shrapnel. Each creature in the 20-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes 8d6 piercing damage on a failed save, or half as much damage on a successful one. The Shrapnel are considered magical weapons for the purposes of overcoming resistance and immunity to nonmagical attacks and damage.  

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd