S1, E4: Beneath the surface of Australia’s pristine waters, marine assailants of all shapes and sizes battle it out for supremacy. Some strike from the shadows. Others wield biological weapons that kill with efficiency. Others conquer with brutish strength and fierce jaws. Join us as we scan the oceans of this island paradise and produce a criminal line-up of the continent’s deadliest cold-blooded killers, including the blue-lined octopus, the peacock mantis shrimp, and one of the most feared predators on the planet, the great white shark.