Bizarre creatures are floating around in our oceans—squishy, slimy, spiky-headed monsters. And they're not even grown up yet! These kids have to go through some drastic changes before they get to be adults. Everyone knows that caterpillars and tadpoles go through metamorphosis, but so do some of the most monstrous creatures under the sea. Take the spiky-headed zoea, somersaulting through the water on her way to becoming a blue crab. Or the gnathiid...