Somewhere off a rocky coast tonight, an octopus is easing out of a crevice no wider than a coin slot. It has no skeleton to stop it. It has three hearts, blue blood, and a nervous system spread through its body like a committee with no chairperson. It tastes the seafloor with its skin, changes color faster than a thought, and may be solving a problem that would stump a toddler. Then, for most of its life, it vanishes again into the dark. Today, October 8, is the day people stop to notice....