Photos that will make you think twice about going swimming

Another small creature that packs a big venomous punch is the blue-ringed octopus. Growing no more than 8 inches in length, this cephalopod feeds on small crabs and shrimp, yet still has enough venom to kill a human. In fact, they have enough venom to kill nearly 30 humans within a matter of minutes. To put it another way, its venom is 10,000 times more powerful than cyanide.