Bake and cool cake in 12 in. x 18 in. x 1 in. jelly roll and cookie pan. Cake is one layer, 1 in. high. Use coffin cutter from 7-pc. coffin cookie cutter set to cut out coffins.
Cover cakes. Melt
white Candy Melts candy according to package directions. Use primary and garden candy colors
to tint portions blue, gray (use black), pink/blue combination (for pink)
and a small amount black. Reserve remaining white candy. Use spatula and melted candy to Use spatula to ice bottom of cakes smooth. Chill until firm, 5 to 10 minutes.
Place cakes, candy side down, on cooling grid over parchment paper-covered pan. Cover cakes with melted candy. Tap to settle. Chill until firm, 10 to 15 minutes. Repeat with a second coat, if needed. Use a knife to even edges
Decorate cakes. Use melted black candy in cut parchment bag to pipe outline locker vents and handles. Use melted candy to attach Monster High icing decoration.