3 days in advance: Make gate, tree and bat. Tint Gum Paste: 8 oz. black, 8 oz. gray. Roll out 1/8 in. thick. Use patterns to cut out shapes. Let dry on cornstarch-dusted boards.
Also in advance: Decorate gate. Follow pattern to pipe tip 3 details in royal icing. Let dry.
Continuing in advance: Decorate bat, using Thinned Royal Icing. Work quickly, 1 section at a time, to prevent drying. Outline wings and legs with tip 2, body with tip 3. Outline section then immediately use damp brush to brush icing outward for shaded effect. Use tip 2 to pipe facial features and to overpipe main details. When dry, attach Cookie Stick to back with Thinned Fondant Adhesive. Let dry.
Finally in advance: Cover base board with 24 oz. violet fondant.