Mermaid Birthday Cake

I'm a little behind on posting this, but here is the cake I made for the girls' party. I got the idea from Family Fun magazine and it worked perfect for our celebration. If you think it looks too hard, it was not bad with a little organization. Here's how it worked.

*2 box cake mixes (I used one strawberry and one butter)
*butter cream frosting (I doubled this)
*2 boxes Bottle Caps candy (theater size)
*strawberry fruit roll-up
*black licorice
*M&Ms (green or blue - only need 2)
*food coloring
*colored sugar

Two days ahead: Make frosting. Color 1/3 white, 1/3 yellow, and 1/3 blue. Refrigerate. Cut cardboard for tray and cover with foil. My tray was 26"x34" and it was just about right.
Day ahead: Bake cakes. One mix will be a standard 9x13 inch and the other should be used to make 12 cupcakes and 1-8" round cake. Let cool and cover. Make colored sugar by adding 1 drop of food coloring to about 1/3 c. sugar. Shake well. Cover. I made blue and yellow sugar.
Same day: Remove frosting from fridge and allow to come to room temperature for easy frosting. Using a piping bag with a star tip, frost cupcakes in a circular pattern with yellow frosting. Cut 9x13 cake into a large triangle and three small ones. Arrange circle and triangle cakes on tray and frost. Circle and one small triangle in white, large and two small triangles in blue. I used a small point tip to squiggle blue frosting for the bikini top. Use BottleCaps to do fin detail, licorice and M&Ms for eyes, fruit roll-up for mouth (I enlisted help for this part)
Add cupcakes to tray. Sprinkle with sugars. Brown sugar also works very well for 'sand' but we needed to move the cake during the party and I didn't want to risk spilling sugar everywhere.