Alex Mustard / Southern / pacific blue-ringed octopus (Hapalochlaena maculosa) swims across the seabed. Port Philip Bay, Blairgowrie, Melbourne, Victoria, Australia.

Jeff Rotman / Scientist holding a poisonous Pacific blue-ringed octopus (Hapalochlaena maculosa) in his hand. The octopus can emmit a fatal neurotoxin through it's saliva when provoked, and there is no known anti-v...

Jeff Rotman / Blue-Ring Octopus (Hapalochlaena maculosa) swimming at night, Eastern Australia, Pacific Ocean.

Brent Hedges / Blue-ringed Octopus (Hapalochlaena maculosa) South Australia, Australia

GEORGETTE DOUWMA / Pacific blue ring octopus {Hapalochlaena maculosa} Sulawesi, Indonesia

Jeff Rotman / Poisonous Blue-ringed octopus {Hapalochlaena maculosa} jets away at night, Australia

Jeff Rotman / Poisonous Blue-ringed octopus {Hapalochlaena maculosa} jets away at night, Australia

Jeff Rotman / Pacific Blue Ring Octopus at night in defence posture. Sydney Australia Hapalochlaena maculosa

Jeff Rotman / Pacific Blue ring octopus {Hapalochlaena maculosa} Eastern Australia, Pacific Ocean

Juergen Freund / Pacific blue ring octopus {Hapalochlaena maculosa} Indo Pacific

Jeff Rotman / Pacific blue ring octopus at night (Hapalochlaena maculosa) Australia

Constantinos Petrinos / Pacific blue ring octopus {Octopus maculosa / lunulata} note enlarged blue rings of agitated animal; toxic species. Lembeh, Sulawesi, Indonesia. Colour change Sequence.