King Cobra can spit its toxin, so it doesn't even need to bite you. Also, only 7 milliliters of the venom can kill 20 humans or one elephant.
This scorpion is tiny but mighty deadly. Its sting can impart a lethal venom with a median lethal dose of 0.25 mg/kg.
The potent venom of this spider is reputedly twice as deadly as cyanide. The effects on a human include increased blood pressure, arrhythmia, coma and death.
Although it's relatively small -- only the size of a golf ball -- its venom is debilitating and deadly. It can cause respiratory failure within 10 minutes and death within 30. One bite can kill up to 26 men, and there is no antidote.
Although the Australian box jellyfish just misses having the most potent venom on this list, it is probably the most deadly. It is large in size yet almost transparent in the water, and its tentacles can sting you with its millions of nematocysts, injecting a hefty amount of venom while holding its victim in place.