National Aquarium - The greater blue-ringed octopus is only about 4 inches across, but it holds enough venom to kill as many as 26 people... within minutes. Look, but definitely don't touch.
blue-ringed octopus - Wiktionary
Blue-Ringed Octopus, small octopus growing to 10cm in length
First aid for bites and stings: Blue-ringed octopus - MyDr.com.au
The blue-ringed octopus communicates and camouflages with its skin | The Kid Should See This
Guided Scuba Dives With Blue-Ringed Octopus, Tour, Mornington Peninsula, Victoria, Australia
Genome‐wide comparisons reveal a clinal species pattern within a holobenthic octopod—the Australian Southern blue‐ringed octopus, Hapalochlaena maculosa (Cephalopoda: Octopodidae) - Morse - 2018 - Ecology and Evolution - Wiley Online Library
A Tourist in Australia Holds a Deadly Blue-Ringed Octopus