The waters of Australia are home to a variety of intriguing octopus and cuttlefish species. One is armed with a special weapon. It's an octopus measuring only 8 cm in length called the blue-ringed octopus. With venom powerful enough to kill humans, this octopus bites and kills prey several times its size. The blue rings on the body are a sign of its deadly poison and are effective to keep away even the most deadly of fish. For years, this octopus was considered invincible, but experts recently discovered it actually has a natural enemy. This episode takes an up-close and personal look at this little octopus cleverly surviving in the hostile sea environment.