As anyone who has studied nature can attest, the world and all its creatures (great as well as small) really are out to get us. Some of their attacks are easy to defend against, and we - in general - know how to survive them. Yet there are creatures on this globe that can snuff us out like a cheap candle in a stiff wind.
Pictured is the yellow-banded poison dart frog, which exudes a slime that can kill you just by a touch. Link