Abstract: A convertible hat device transitions into a ball when the hat is turned inside out. The device includes a flexible cover. An opening extends into the cover for accessing an interior of the cover. The cover is positionable to form a primary ball having a circular perimeter edge. A plurality of elongated tails is coupled to the cover. Each of the tails is flexible and positionable within the opening to store the tails within the interior of the cover. Each of the tails has an associated base. A receiving space is formed proximate the base of the tails wherein the receiving space is configured to receive an entirety of the cover therein. The exterior surface of the cover forms a crown of a hat for receiving a head of a user when the cover is positioned within the receiving space.