The ornamental design for an antlersink, as shown and described.
FIG. 1 is a perspective view of an antler sink showing an embodiment of the design of the invention. The broken line showing of a structural feature, in this and the following related Figures, is included for the purpose of illustrating non-claimed subject and forms no part of the claimed design.
FIG. 2 is a top plan view thereof.
FIG. 3 is a bottom view thereof.
FIG. 4 is a side elevation view thereof.
FIG. 5 is an opposite side elevation view thereof.