An agitator is for use in a shaker. The agitator comprises a tetrahedral body having four planar faces, four vertices, and six edges, each edge traveling between each of the vertices. Each vertex is rounded off and configured to forcibly contact the container wall and an entirety of the bottom upon shaking the vessel. These rounded vertices create a propeller-like spinning and tumbling motion through the liquid-powder mixture when the vessel is vigorously shaken up and down, and scalloped edges of the agitator produce additional turbulence to efficiently blend a liquid/powder mixture.