1 day in advance, make ears. Knead 1/8 teaspoon of Gum-Tex into 1 oz. purple fondant. Using 9 in. fondant roller, roll out fondant 1/8 in. thick. Using the smooth side of the E oval cutter, cut out two shapes for ears. Let dry on dusted lightly cornstarch-dusted cake board for 24 hours. Reserve remaining fondant.

Bake cake. Bake and cool one layer 2-in. high cake. Prepare buttercream icing according to recipe. Using spatula, ice cake lightly to prepare for fondant covering.

Cover cake. Roll out reserved purple fondant 1/8 in. thick and cover cake. Also using hippo snout pattern and knife, cut out hippo snout and tail from purple fondant rolled 1/8 in. thick. Attach to cake with damp brush.

Add details to cake. Roll out black fondant, 1/16 in. thick. Using the smooth side of the E of double sided round cutter, cut out two eyes. Using narrow end of tip 6, cut out six dots for whiskers. Using the smooth side of the D oval cut out, cut two nostrils.

Attach eyes and whiskers using a damp brush. Roll nostril shapes to widen slightly and attach with damp brush to snout shape. Roll out a 1/4 in. ball of white fondant to 1/16 in. thick. Using narrow end of tip 10, cut out two dots and attach to eyes with damp brush for highlights.

Make small amount fondant adhesive. Trim two lollipop sticks to 3 in. each. Attach one ear to each stick with adhesive. Let dry 1 to 2 hours.

Add ears. Insert lollipop sticks with attached ears into top corners of cake, approximately 3/8 in. down from top edge.

Add tail. Position tail to cake on plate or board with damp brush.