Water to Molten Iron

You transmute a volume of water that you can see into molten iron. Choose a space of 10 connected 5-foot cubes, then, the liquid water within that space is transformed into molten iron. Any creature that starts their turn in the molten iron, or enters it for the first time on their turn, takes 6d10 fire damage and must pass a Strength saving throw or have their movement speed reduced to 0. In addition, the molten iron is considered difficult terrain.

The surface of the iron will harden after 10 minutes exposed to air, or 1d6 rounds if exposed to water. While it is cooling, the iron stays near the shape it was when it was trasmuted. Once the shell hardens, the entire block hardens, and it has 18 AC and 50 health. When its health reaches 0, the iron crumbles into irregular chunks.