2. Box Jellyfish
The box jellyfish is as powerful as it is scary. Its venom can kill instantly as it contains toxins that attack the skin cells, heart, and the nervous system. Found mainly in Northern Australia, the box jellyfish is often considered by many as the most venomous marine animal known to mankind. What makes the box jellyfish even more shockingly scary is the fact that, unlike other jellyfish that simply drift, it can actually move voluntarily. We hate jellyfish!