Visiting Florida? South America? Keep an eye out for machineel trees, because as Sploid points out, while they look perfectly harmless, they can be deadly. It's a pretty impressive (and lethal) resume: Standing under one in the rain can cause blistering when the drops hit you, its sap can give you an allergic reaction, burning its wood can cause blindness, and eating its apples—which Christopher Columbus called "little apples of death"—can apparently kill you.
​This tree causes instant blisters, blindness and death