1) Golden Dart Frog
The Golden Dart Frog is the most lethal of the poison dart frogs. It keeps its poison in glands beneath its skin.The poison is a powerful nitrogen compound known as a batrachotoxin. If absorbed into the bloodstream through the eyes, nose, a cut, or even directly through the skin, the poison is capable of causing paralysis convulsions, and death. One drop can cause the human heart to stop beating.
2) Box Jellyfish
On each tentacle, there are around half a million darts. These microscopic darts are full of venom, called nematocysts. The nematocysts shoot out when triggered by touch and can penetrate human skin in less time than it takes you to blink. . The toxin attacks the heart, nervous system, and skin cells. After being injected with this poison you may experience paralysis, cardiac arrest, and even death, all within a few minutes of being stung.
3) Deathstalker Scorpion
They are very aggressive and antisocial. Its venom is a powerful mixture of neurotoxins. When the venom does prove fatal it is because the poison has affected the left ventricle of the heart causing fluid in the lungs and respiratory failure.This venom can cause coma, fever, paralysis, convulsions, and even death. Any envenomation runs the risk of anaphylaxis, a potentially life-threatening allergic reaction to the venom.
4) Black Mamba
The black mamba has a reputation for being highly aggressive and very the fast. It is capable of striking at considerable range and occasionally may deliver a series of bites in rapid succession.
The venom of the black mamba is extremely toxic - chiefly composed of neurotoxins, specifically dendrotoxin which is “fast-acting.” Commonly causing collapse in humans within 45 minutes or less from a single bite. It shuts down the nervous system and paralyzes victims. Without effective antivenom therapy, the fatality rate from a Black Mamba bite is 100 percent- death typically occurs in 7–15 hours -