You brandish the weapon used in the spell's casting and make an attack with it against one creature within your reach. On hit the creature suffers the weapon attack's normal effects, and the creature must make a Consituiton saving throw. On a failed save, the creature becomes petrified until the end of your next turn. When a creature is petrified in this way, they are frozen in ice and do not have resistance to cold damage from the petrified, the target still retains any resistance to cold damage from other sources.

At Higher Levels.  At level 5, when the creature is hit by the weapon, that target takes an additional 1d8 cold damage. At level 11 this damage is increased to 2d8 and 3d8 at level 17.