My 2 year old LOVES the water! She calls it "da wa", hence the name "cake in da wa". I surprised her with a water-themed cake for her birthday and she was so excited! She screamed, jumped, and danced around so much when she saw it!
It was very simple to do. I frosted a normal rectangle cake with blue frosting and added all sorts of gummy sea animals like octopus, sharks, fish, sea turtles, and frogs. Then I filled in empty spaces with green seaweed frosting and white bubbles.
Sorry, I haven't posted enough to add pictures but I put a link at the end (that hopefully works!)