The most well-known of the octopus's defense mechanisms is its ability to squirt clouds of ink into the water some octopi use this cloud of ink as camouflage after squirt the ink the octopus retreats into the ink cloud where the predator cannot see it other octopi use the ink cloud as a decoy if a large intelligent predator such as a shark knows that octopi use ink clouds for camouflage it might simply attack the ink cloud blindly hoping to make contact with the octopus inside however some sneaky octopi will release the ink cloud in one direction and scurry away in another direction leaving the predator with nothing but a mouthful of ink in addition to confusing predator's sense of sight these ink clouds also confuse their sense of smell the ink is composed primarily of melanin (the same chemical that gives human skin its color)which can shut down a predator's sense of smell if an octopus cannot be seen or smelled it has a much higher chance of escaping an attack