Prepare cake mix as directed on package, adding vanilla to batter. Bake as directed on package in 13x9-inch baking pan. Cool cake in pan on wire rack.
Cut cake as shown in diagram, to form body, head and ears. Cut out small circle from scraps for the tail or use a marshmallow.
Assemble cake to form a bunny shape. Stir about 7 drops of desired Neon color into frosting. Spread tinted frosting on cake. Tint coconut the same color as frosting (see Tip). Gently pat onto frosted cake. Sprinkle Neon Green-tinted coconut around bottom of bunny for grass effect. (If desired coconut may be omitted.)
Use jelly beans, gumdrops and licorice strings for the eye, nose and mouth.