Blue-Ringed Octopus Bite: The blue-ringed octopus is not an aggressive marine animal; however, when it bites it has a deadly venom. If you are bitten by a blue-ringed octopus it is a medical emergency. Symptoms include pain, bleeding, numbness, nausea, vomiting, changes in vision, and difficulty breathing. If medical care is not provided, the patient will likely go into respiratory failure, which leads to cardiac arrest and death.