Make layered cake. Prepare batter following recipe directions. Bake and cool two 6 in. cake layers. Prepare buttercream icing following recipe directions. Level one layer, fill and stack layers, positioning layer with crown side on top, on cake circle for a 2-layer cake, 6 in. high.
Ice cake. Tint portion of icing black; reserve majority white. Use spatula and white icing to mound icing, if needed, on top of cake and then to ice cake, blending mound and cake sides into each other for ghost shape.
Decorate cake. Use tip 2A, a cut disposable decorating bag and white icing to pipe pull-out ball for arms. Use tip 12, a cut disposable decorating bag and black icing to outline and fill in eyes and mouth. Pat smooth with finger dipped in cornstarch.