Its yen to get loose is probably linked to an instinctive urge to change dens every week or two. An octopus in the open sea might seem easy pickings for predators such as moray eels, sea lions and bigger octopuses, but the octopus can marshal a dazzling array of defenses. Like a squid, it can disorient a pursuer with a burst of purplish-black ink. Should it lose an arm to the jaws of a predator, it can grow a new limb. More impressive still, an octopus can change color in less than a second.
Chameleons are just dead-boring compared to octopuses.
In its den, an octopus will often simply lie hidden, its arms coiled, before unrolling one to snag a passerby with the suckers at the tip. While swimming, its preferred attack posture is to parachute gently down with all eight arms outstretched and envelop its prey in the web connecting the arms. Having wrapped up its victim, an octopus holds it against its underside and bites it with a retractable, parrotlike beak. Octopuses also crawl over reefs, probing with their arms for hidden prey. The salivary glands of all octopuses secrete a chemical that helps disable its prey and breakdown its muscle tissue.