Greater Blue-ringed Octopus

The greater blue-ringed octopus (Hapalochlaena lunulata) is one of three (or perhaps four) species of venomous blue-ringed octopuses. Unlike its southern brethren, the Blue-lined and Southern Blue-ringed octopuses that are found only in Australian waters, the range of the greater blue-ringed octopus spans the tropical western Pacific Ocean. Greater blue-ringed octopuses can weigh between 10 and 100 grams.