The ornamental design for a casketcover, as shown and described.
FIG. 1 is a perspective view of the casket cover completely covering a casket/coffin; and,
FIG. 2 is a top plan view thereof, the bottom plan view being a mirror image thereof.
The broken lines such as those showing the casket, the indicia on the casket cover, and the peripheral design on the casket cover are for environmental purposes only and form no part of the claimed design.