7 Blue-Ringed Octopus-ThinkstockPhotos-525876966.jpg

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Commonly found in the Pacific and Indian Oceans are the venomous blue-ringed octopi. Don’t let their small size fool you, they like to hide in crevices and camouflage – if you antagonize them, they will attack. Their venom contains tetrodotoxin, which is a neurotoxin that is powerful enough to kill humans.