Flatten gumdrops with rolling pin. Cut out star and moon shapes. Set aside.
In 3-quart saucepan, melt butter and chocolate chips over low heat, stirring frequently, until smooth. Stir in marshmallow creme until completely melted. Remove from heat. Stir in cereal until well coated.
To form brim of hat, shape 2 cups cereal mixture into 6-inch round; place on serving platter or tray. Shape remaining mixture into cone, 4 inches in diameter at base and 7 inches tall. Place cone on round. If desired, bend tip of cone.
While cereal mixture is still sticky, attach star and moon shapes. Wrap chewy fruit snack around bottom of cone for hatband. Break or cut into pieces to serve.