The fruit in question belonged to the manchineel tree (Hippomane mancinella), sometimes referred to as 'beach apple' or 'poison guava'. It's native to the tropical parts of southern North America, as well as Central America, the Caribbean, and parts of northern South America. The plant bears another name in Spanish, arbol de la muerte, which literally means "tree of death". According to the Guinness World Records, the manchineel tree is in fact the most dangerous tree in the world. As explained by the Florida Institute of Food and Agricultural Sciences, all parts of manchineel are extremely poisonous, and "interaction with and ingestion of any part of this tree may be lethal". Manchineel belongs to the large and diverse Euphorbia genus, which also contains the decorative Christmas poinsettia. The tree produces a thick, milky sap, which oozes out of everything - the bark, the leaves and even the fruit - and can cause severe, burn-like blisters if it comes into contact with the skin. This sap contains a range of toxins, but it's thought that the most serious reactions come from phorbol, an organic compound that belongs to the diterpene family of esters. Because phorbol is highly water-soluble, you don't even want to be standing under a manchineel when it's raining - the raindrops carrying the diluted sap can still severely burn your skin.