Make dough, chill, and roll out to 1/4-inch thickness. Cut out dough using a 3-inch gingerbread man cut out. Bake according to recipe instructions. Cool completely.
Make royal icing according to directions; excluding the vanilla extract.
Use a piping bag fitted with a small circular piping tip to outline and flood cookies in the shape of a skull, bones, and rib cage.
Tint royal icing black, purple, pink, and blue for decorating. Using piping bags fitted with small circular tips, create eyes, nose, and mouth out of black-tinted royal icing. Decorate the eyes using blue-tinted food coloring, and the head piece and cheeks using pink-and-purple-tinted food coloring.
Allow cookies to dry at room temperature. Do not cover or stack cookies until icing has completely dried. Once cookies have dried, layer the cookies with parchment or wax paper in between the layers of cookies if stacking.