Evolution has given some creatures strange powers that help them survive. The tiny, tropical coconut octopus has monocular vision, it uses venom to deter predators, it has developed bipedal locomotion, and its defense includes camouflage. It collects discarded shells and builds a shelter, the only invertebrate with this cognitive ability. The Australian short-beaked echidna, is a mammal with a bird like head; it eats worms and insects, lays eggs and carries its young in pouches. They have a large neocortex and a slow metabolism; the male has a rare four-headed penis, and their defense includes quills, camouflage, burrowing and swimming. The mastigoproctus giganteus, an arachnid commonly called a vinegaroon, has 8 eyes, powerful claws and a whip-like tail. It defends itself by precision spraying of concentrated acetic acid from the base of its tail, its front legs help detect prey. The tiny sunburst diving beetle carries an air bubble below the water surface to provide oxygen, and competitors have learned to burst these bubbles. Their 6 eyes help them hunt, and the males' suction cups help them cling to their mates.