The ornamental design for a objectslingingdevice, as shown and described.
FIG. 1 is a perspective view of the object slinging device of the instant invention;
FIG. 2 is a front view thereof, a back view forming a mirror image of the front view, not shown;
FIG. 3 is a left side view thereof, a right side view forming a mirror image of the left side view, not shown;
FIG. 4 is a top view thereof; and,
FIG. 5 is a bottom view thereof.
The broken line showing in FIGS. 1 and 2 is for the purpose of illustrating portions of the object slinging device that forms no part of the claimed design.