Blue-ringed Octopus (Hapalochlaena lunulata) are 3 or 4 octopus species that live in tide pools & coral reefs in Pacific & Indian Oceans. They are 1 of the world's most venomous marine animals. Despite their small size & relatively docile nature, they can prove a danger to humans. They can be recognized by characteristic blue & black rings & yellowish skin. When agitated, the brown patches darken dramatically, & iridescent blue rings or clumps of rings appear & pulsate within the maculae.
The blue-ringed octopus a beautiful creature, a small cephalopod is deadly. The blue-ringed octopus appears grey or beige with light brown patches when it is at rest, but when agitated its 50 or 60 bright blue rings appear and pulsate with color, as a warning. Inside the salivary glands of the blue-ringed octopus live colonies of bacteria that produce tetrodotoxin, the potent neurotoxin found in pufferfish and other animals. A bite from a blue-ringed octopus can completely paralyze.