Blue-ringed Octopus flashing its iridescent blue rings

The greater Blue-ringed Octopus, a small, vibrant and highly venomous cephalopod. The rings of a blue-ringed octopus become particularly vivid when it feels threatened or agitated, becoming flashing iridescent blue rings. Following this warning display the blue-ringed octopus will bite and inject an extremely potent venom strong enough to kill a human. There is no anti-venom for this poison. 
 
They like to live in crevices amongst rocks, inside seashells, and discarded bottles and cans because of its soft-bodied vulnerability, and are nocturnal, emerging at night to hunt crustaceans and small fish.
 
Scientific Name:  Hapalochlaena lunulata