12. Coastal Taipan

One of the deadliest snakes worldwide — thank you, Australia — the coastal taipan’s venom is highly toxic. In fact, without antivenom, there’s been only one known survivor, and the toxin turned the victim’s blood temporarily black. Its neurotoxic poison attacks the nervous system and prevents the body from being able to clot blood, meaning someone who is stung can die in as little as half an hour.