Follow the package directions for rectangular 13 x 9 cake. Let cool. Cut a 2 inch wide strip off one end. Cut the rest in half. Frost one half. Set 2 in. strip in the middle of the frosted half of cake & frost. Frost other half. Set the leftover half of the cake on the first half so "open" chest on one side, hinged other. Touch up frosting. Add candy necklaces, broken Jolly Roger candy jewels and chocolate coins spilling out of chest.