Make cake. Prepare batter following recipe directions. Bake and cool cake according to pan package directions using half the mold. Prepare buttercream icing following recipe directions. Prepare cake for fondant covering. Reserve remaining icing.
Build facial features on cake. Tint 16 oz. fondant green. Use 5 oz. fondant to extend top of cake for elongated head. Roll 7/8 in. ball of fondant into log for eyebrow, and roll 1 1/4 in. ball of fondant into log for mouth. Roll 1 oz. white fondant into ball and flatten for eyeball. Place fondant pieces on iced cake.
Use 20 in. fondant roller with orange guide rings to roll out remaining green fondant 1/8 in. thick. Cover cake with fondant. Reserve remaining green fondant.
Make eyeball and eyelid. Use smallest round (1 3/4 in. dia.) cutter from set to cut circle for eye to come through. Tint 1/2 in. ball of white fondant blue green. Roll into a ball and flatten for iris. Tint 5/16 in. ball of white fondant black. Roll into a ball and flatten for pupil. Use a damp brush to attach pupil to iris and then iris to eyeball.
For eyelid, use 9 in. fondant roller with purple guide rings to roll out reserved green fondant 1/8 in. thick. Use largest round cut-out to cut circle and then use knife to cut circle in half. Use damp brush to attach half circle to eyeball.
Make mouth. Use small veining tool from set to indent fondant for mouth.
Make hat. Tint 5 oz. white fondant dark blue. Roll fondant into ball and then flatten, 2 3/4 in wide. Use knife to cut 3/4 in. off and shape into hat, 2 3/4 in. wide x 1 1/2 in. tall. Use 9 in. fondant roller with purple guide rings to roll out remaining dark blue fondant 1/8 in. thick. Use large round cut-out to cut out hat bill. Use knife to trim with a slight curve to match hat, 1 in. long x 2 1/4 in. wide. Use damp brush to attach hat bill to hat.
Tint reserved buttercream blue and a small portion black. Reserve some white. Use tip 2 and blue icing to outline and fill in letters. Use tip 2 and white icing to outline letters and to pipe eyeball. Use finger dipped in cornstarch to pat smooth. Use tip 2 and black icing to pipe pupil. Pat smooth.
Use damp brush to attach hat to head.
Make horns. Roll out 7/8 in. ball of white fondant into two logs. Shape into horns, each 1 in. long x 1/2 in. wide. Use damp brush to attach horns to side of head.