After drinking this potion, you can use an action to exhale a cloud of icy fog in a 20-foot cube originating from you. The cloud spreads around corners, and its area is heavily obscured. It lasts for 1 minute or until a wind of moderate or greater speed (at least 10 miles per hour) disperses it. When a creature enters the cloud for the first time on a turn or starts its turn there, that creature must succeed on a DC 13 Constitution saving throw or take 2d4 cold damage. The effects of this potion end after you have exhaled one fog cloud or 1 hour has passed. This potion has a gray, cloudy appearance and swirls vigorously when shaken.