Prepare cake mix as directed on package, adding vanilla.
Bake as directed on package for cupcakes. Cool cupcakes on wire rack.
Dip open end of each ice cream cone into melted chocolate. Attach to chocolate wafer cookies to make the witch’s hat. Let stand 30 minutes to allow chocolate to harden. Tint frosting green with 1/2 teaspoon green food color. Frost cupcakes. Place witch’s hat on each cupcake. Use candy-coated pieces for the eyes and gum drops, cut into triangles, for the nose. Cut string licorice into assorted lengths for the hair.