The ornamental design for a shakerball, as shown and described.
FIG. 1 is a side-top perspective view of a shaker ball showing my new design;
FIG. 2 is a front elevational view of the shaker ball shown in FIG. 1;
FIG. 3 is a rear elevational view of the shaker ball shown in FIG. 1;
FIG. 4 is a left side elevational view of the shaker ball shown in FIG. 1;
FIG. 5 is a right side elevational view of the shaker ball shown in FIG. 1;
FIG. 6 is a top plan view of the shaker ball shown in FIG. 1; and,
FIG. 7 is a bottom plan view of the shaker ball shown in FIG. 1.
The broken line portions of the drawing figures are included to show unclaimed subject matter only and form no part of the claimed design. In particular, the logo on the top and bottom of the shaker ball shown in broken lines forms no part of the claimed invention.