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. 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.