5. Blue-Ringed Octopus
Source: Iconosquare
The beautiful Blue-Ringed Octopus is one of the world’s deadliest marine animals. It inhabits tidal rock pools of the southern coasts and can either inject venom or emit a toxic cloud. After envenomation, death can occur in under 2 hours.
There is no anti-venom yet developed that can save the victims of this strange animal’s bite, which is 10,000 times more toxic than cyanide.