The common octopus would be unique for its appearance alone, with its massive bulbous head, large eyes, and eight distinctive arms. But by far the most striking characteristic of the octopus is the wide array of techniques it uses to avoid or thwart attackers.
Its first—and most amazing—line of defense is its ability to hide in plain sight. Using a network of pigment cells and specialized muscles in its skin, the common octopus can almost instantaneously match the colors, patterns, and even textures of its surroundings. Predators such as sharks, eels, and dolphins swim by without even noticing it.