The blue-ringed octopus exists.
The blue-ringed octopodes ( genus Hapalochlaena ) are three octopus species that live in tide pools and coral reefs in the Pacific and Indian Oceans , from Japan to Australia . They can be identified by their characteristic blue and black rings , and yellowish skin . When the octopus is agitated , the brown patches darken dramatically , iridescent blue rings , or clumps of rings , appear and pulsate within the maculae .