Dye the vanilla frosting (if using) blue. If you choose to use all chocolate frosting, you'll just need lots of blue and green sprinkles.
Bake the cake and cool completely. If making a layer cake, adhere the two layers together with frosting.
Frost a crumb coat over the entire cake.
Then lay out your beach line. Your cake can be half ocean, half beach or more one than the other. Frost one part with chocolate and the other blue.
With your knife or spreader, rough up your ocean a bit so that you’ve got some waves going. If you have a surfer toy, make sure he can catch a wave.
Sprinkle blue and green sprinkles all over the “water” side of the cake. Sprinkle graham cracker crumbs or brown sugar over the “beach” side. Place candy rocks along the shore line. You can also use toy rock formations if you have them.
Using the small tube of white frosting, pipe some "sea foam" where the ocean meets the shore. Pipe more along the tips of the "breakers" that you roughed up in the blue frosting.
Pack brown sugar into a small cylinder container (such as a toy bucket or sauce cup) for a sand castle.
Craft a paper flag and tape it to the toothpick. Insert it into your sandcastle.
Place your other toys and candies on the cake. Fruit snacks can represent fish swimming in the sea.