Juergen Freund / Blue-ringed octopus (Hapalochlaena lunulata) swimming through water, Batangas, Philippines

Juergen Freund / Tropical blue-ringed octopus (Hapalochlaena lunulata) hunting. Lembeh Strait, North Sulawesi, Indonesia.

Alex Mustard / Bue ring octopus (Hapalochlaena lunulata) walking across the sea bed. Dauin, Dauin Marine Protected Area, Dumaguete, Negros, Philippines. Bohol Sea, tropical west Pacific Ocean.

Alex Mustard / Blue ring octopus (Hapalochlaena lunulata) walks across the sea bed. Dauin, Dauin Marine Protected Area, Dumaguete, Negros, Philippines. Bohol Sea, tropical west Pacific Ocean.

Alex Mustard / Large blue ring octopus (Hapalochlaena lunulata) swimming just above the sea bed. Dauin, Dauin Marine Protected Area, Dumaguete, Negros, Philippines. Bohol Sea, tropical west Pacific Ocean.

Gary Bell/ Oceanwide / Greater Blue-ringed Octopus (Hapalochlaena lunulata), Great Barrier Reef, Australia

Pascal Kobeh / Greater blue-ringed octopus (Hapalochlaena lunulata) , Sulu sea, Philippines

Alex Mustard / Blue ringed octopus (Hapalochlaena lunulata) moving across the seabed. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Portrait of a Blue ringed octopus (Hapalochlaena lunulata) on an algae covered rock. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

David Fleetham / Tropical blue-ringed octopus (Hapalochiaena lunulata) Philippines.

David Fleetham / Tropical blue-ringed octopus (Hapalochiaena lunulata) swimming over seabed, Philippines.

David Fleetham / Tropical blue-ringed octopus (Hapalochiaena lunulata) Komodo, Indonesia.