This video shows how to make a mermaid birthday cake that would be perfect for a little girl. To make the mermaid take a fashion doll, or a Barbie doll, and wrap her legs in plastic wrap. Now cover her in green and blue fruit roll-ups to form the mermaid's tail. You will need about three strips to make the entire dress and tail. The fruit roll-ups will stick to itself. For the cake you will need two 8 inch rounds and a smaller cake baked in a custard cup. Make sure the cakes are flat on top, cutting of the domes if necessary. Frost the top of an 8 inch round and put the second cake on top. Put the small cake on top to the side, adhering with more frosting. To form a seat for the mermaid cut a triangular area out of the small cake. Now frost the entire cake with a water theme. Add the fashion doll mermaid, and your cake is ready!