Black Ice Knife

You create a shard of black ice and fling it at one creature within sight. Make a ranged spell attack against the target. On a hit, the target takes 1d12 Piercing damage. Hit or miss, the shard then explodes. The target and each creature within 10 feet of it must succeed on a Dexterity saving throw or take 3d6 Cold damage. The knife goes through all magical protection that would block a level 0-3 spell.

Using a Higher-Level Spell Slot. The Cold damage increases by 1d6 for each spell slot level above 1.