The blue-ringed octopus is renowned for being one of the world’s most venomous marine animals, despite reaching a maximum of 10 cm in size. Their venom, delivered from the beak, can inflict total body paralysis. While resting, these octopuses are a beige or dark yellow colour, but their bodies flash 40 to 60 glowing blue rings when provoked. The blue-ringed octopus is found in the Pacific and Indian Oceans and usually feeds on small crabs and shrimps.
Blue-ringed octopuses' venom is 1 000 times more powerful than cyanide.
The blue rings of these octopuses are an example of aposematism, where animals use bright colours as a warning for predators.
There are believed to be roughly 10 species of blue-ringed octopus, but only four have been given scientific names.