Magnetite Shard (TP)

You fling a supercooled piece of magnetite at a point you can see within range, where it detonates in an explosion of icy, metallic shards. Each creature in a 20-foot-radius sphere centered on that point must make a Dexterity saving throw, taking 4d6 cold damage and 3d6 piercing damage on a failure, or half as much damage on a success. Creatures made of a ferrous material or wearing ferrous armor have disadvantage on this saving throw.

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