The ornamental design for a golfballcorncobholder, as shown and described.
FIG. 1 is a top isometric view of a golf ball corn cob holder showing the golf ball handle and tee shaped prong arrangement of my new cob holder design;
FIG. 2 is a top view thereof, the bottom view being a mirror image thereof;
FIG. 3 is a right side view thereof, the left side view being a mirror image thereof;