Cold Snap

you call forth a wave of frigid air that fills a 40-foot cube originating from you, then momentarily freeze the entire area solid. Each creature in the area must make a Constitution saving throw. A target takes 8d6 cold damage on a failed save, or half as much on a successful one.

A creature killed by this spell becomes a frozen statue until it thaws.

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.