The Bloodforge Arena

You create a wall of ice on a solid surface within range. You can form it into a hemispherical dome or a sphere with a radius of up to 10 feet, or you can shape a flat surface made up of ten 10-foot-square panels. Each panel must be contiguous with another panel. In any form, the wall is 1 foot thick and lasts for the duration. If the wall cuts through a creature's space when it appears, the creature within its area is pushed to one side of the wall and must make a dexterity saving throw. On a failed save, the creature takes 10d6 cold damage, or half as much damage on a successful save. The wall is an object that can be damaged and thus breached. It has AC 12 and 30 hit points per 10-foot section, and it is vulnerable to fire damage. Reducing a 10-foot section of wall to 0 hit points destroys it and leaves behind a sheet of frigid air in the space the wall occupied. A creature moving through the sheet of frigid air for the first time on a turn must make a constitution saving throw. That creature takes 5d6 cold damage on a failed save, or half as much damage on a successful one.