Bake and cool cake. Trim off shoes, socks and backpack. Ice sides and background areas smooth. Using tip 3, outline arms, hair, face and features; outline and pipe in tongue and whites of eyes (smooth with finger dipped in cornstarch). Use tip 4 to fill in mouth and irises, tip 3 to pipe dot pupils. Using tip 2, add dot highlights to eyes; outline bracelet and pipe dot pearls. Cover arms, face and hair with tip 16 stars. Insert fins, supporting tips with marshmallows, if necessary. Tint 4 oz. fondant green, 1 oz. dark pink, 1 oz. light pink; roll out 1/8 in. thick. Use patterns to cut tail and shirt; attach to cake over thin layer of icing. Use wide end of tip 2A to imprint semicircle scales on torso. Cover neck and belly with tip 13 stars. Cut 3/4 in. wide fondant strips for ruffles: 2 in. long for sleeves, 7 in. long for waistband. Gather into pleats and attach with damp brush, trimming as needed to fit. Outline shirt and ruffle edges with tip 3; paint ruffle edges with pink Pearl Dust mixed with
extract. Grate colored chalk through tea strainer to a fine powder. Dust torso with green chalk dust, fins with purple and blue. Outline torso, fins and add detail lines with tip 3. Outline crown with tip 3. Using white fondant, cut 3 circles and 2 stars with smallest Cut-Outs; outline with tip 1. Attach fondant trims to crown; position crown on cake.