Bake and cool candy corn cookie and witch's head cookie.
Place candy corn cookie on cooling grid positioned over cookie sheet. Thin black icing to pouring consistency; place in cut decorating bag and use to cover cookie; let dry.
For witch's head, use tip 3 and green icing to pipe in face (smooth with finger dipped in cornstarch). Press witch's head cookie cutter onto cookie to imprint facial features. Pipe tip 4 whites of eyes, tip 3 black pupils (smooth with finger dipped in cornstarch). Pipe in tip 2 green eyelids. Pipe tip 3 outline mouth in black, pipe-in tip 2 red mouth. Outline and pipe-in hat with tip 3 in black. Pipe tip 3 violet hatband and tip 3 yellow buckle. Pipe tip 3 orange pull-out hair. Add tip 3 pull-out nose in green.
Attach cookie head to cookie body with icing and position on waxed paper. Attach pretzel stick to body with black icing. Pipe tip 4 bristles and band on broom in yellow. Pipe 12 left arm in black and hand with tip 3 in green. Pipe tip 12 right arm from behind in black and hand with tip 3 in green.
Combine lemon yellow and leaf green icing colors for green shown. Combine lemon yellow and golden yellow icing colors for yellow shown. Combine red-red and christmas red icing colors for red shown. Combine violet and rose icing colors for violet shown.