Not sure how they come up with 'deadliest animal'. Wikipedia lists scorpions as only 8th most deadly to humans. Freshwater snails and dogs kill at least 3x more people, and mosquitoes kill over 200x more people.
1. Box Jellyfish
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.
The venom's toxins can cause extreme pain, paralysis, delirium, shock, cardiac arrest and even death within minutes. The jellyfish has enough venom to kill 60 adults.