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.