The Southern Blue-Ringed Octopus is small, not usually exceeding 20cm in size. Its colour is yellowish, with dark patches and it is commonly found in and around rubble and rocky reefs. It gets its name from the intense neon blue rings that become visible when they are threatened. This species has highly toxic venom, and it has been responsible for several human deaths. It should be treated with utmost caution, and if a bite occurs it is essential to seek emergency medical attention.