People may be wondering why I saved this little guy for last. Wait until you read about the Assassin Caterpillar. It can be almost impossible to even see this creature because it blends into its natural habitat so well. Therefore, humans can encounter it randomly. People have known about the creature for some time, but only recently have they known that it was massively poisonous. So far, in the last 20 years it has caused hundreds of deaths. In just the last few years, there have been around 300 known envenomings, many resulting in death or long term hospitalization. When Brazilian scientists found out about the creature, they quickly prepared the antivenom. It causes "disseminated intravascular coagulation," which is a fancy way of saying that it makes you bleed and prevents clotting. The caterpillar will give you something called "bruised blood." It's just like being hit in the face or arm and getting a bruise. Your body will swell up due to the blood, among other things. You feel pain there for a while, you're tender, etc. However, imagine this happening to your inner biological makeup, your blood in particular. Your bruised blood cannot function well, causing severe issues. The poison will also attack human cells. More specifically, it attacks protein cells, causing them to leak and preventing them from clotting. This virtually kills off the platelets. Due to all of this, you start to bleed internally, which spreads throughout your organs. It will eventually cause compression and eventually brain death. You'll bleed externally, too, just to add more fun to the party. All of this happens immediately when the poison enters your body. Normally, to do enough damage to kill it would have to sting you 20 to 100 times. The funny thing is that most people who run into these guys end up getting that without even realizing it. Also, people do it in obvious ways such as stepping on it or putting your hand on a tree where it is hanging around. Scientists were baffled as to what changed with this animal, since no well-known attacks happened for millennia. However, a large number of attacks have recently occurred in just the Brazilian area. Something has caused this caterpillar to realize its power, and it's quickly becoming one of the deadliest animals in the world . Several studies continue to be done on the ecosystem in Brazil where these venomous creatures are located. But so far, nothing major has been figured out, at least nothing that we didn't already know.