You stomp your foot, releasing a wave of frost in a 30-foot cone in front of you, leaving a surface of ice in the area. The ice surface is difficult terrain, and each creature that enters the area for the first time on a turn or starts its turn inside must make a Dexterity saving throw. On a failure, a creature takes 3d6 bludgeoning damage, and is knocked prone.   The ice surface lasts for the duration or until it is cleared by some environmental effect, such as being lit on fire.