Blue-ringed Octopus
Alternative names: Hapalochlaena
The Blue-ringed octopus is one of the deadliest animals in the sea and can be found in the Pacific and Indian Oceans, from Australia to Japan.
Its name was given because of its bright blue rings that shows when the octopus feels threatened. In case the predator won't leave, the octopus will attack by injecting a venom that causes paralysis followed by death. This octopus has enough venom to kill 26 human adults at the same time and unfortunately there is no known antidote.