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.
There aren't modern records of deaths, but it has been noted historically. In fact, the explorer Juan Ponce de Leon is said to have died after being hit by an arrow tipped with machineel poison. Some, but not all, areas mark the trees as a warning. In addition to appearing in Florida and northern South America, the endangered species is found in Central America, the Bahamas, and the Caribbean, Sploid notes.