Blue-ringed octopus

The blue-ringed octopus is a small, 6-inch octopus that lives in tide pools[?] in the Pacific, in places from Japan to Australia. It tends to blend into its environment until provoked, when it turns quickly into a bright yellow creature with blue rings. It hunts small crabs, but will bite an attacker, even a human if provoked or stepped on.

Its saliva, which can be instilled through a bite or it can be spit, contains the bacterial poison Tetrodotoxin, to which there is no known antidote. Tetrodotoxin can cause cardiac and respiratory arrest[?]. First aid treatment is CPR, and hospital treatment involves respiratory assistance until the toxin is washed out of the body.

There are two species. Hapalochlaena lunulata[?] is larger and rarer. Hapalochlaena maculosa[?] is smaller. Both are equally venomous.