oganberries, discovered in 1398 by Logan Von Schlack, are red, hard-shelled berries about the size of grapes that grow on trees. Von Schlack, who wasn't educated in biological sciences, didn't realize that berries don't grow on trees, and that, therefore, loganberries aren't actually berries, but a diminished, plagued form of apple.
The berries themselves have a hard, rock-like exterior, similar to that of a crabapple or a medium-sized slab of granite. Due to the decayed nature of the berry, the inside isn't solid; instead it contains a highly basic liquid. While extremely nutritious and succulent when treated correctly, in its original form it is corrosive to the touch and very dangerous. Of course, the thickness and toughness of the shell stops this liquid from being released in the loganberries' natural environment.
Most interesting about the liquid inside is that it reacts violently to certain chemicals in certain animals' urine. A famous case in 1666 had four loganberries falling from their tree and shattering, spilling their insides on the fresh urine of a hunting dog that had recently passed the tree. The resulting explosion deafened those nearby and was the cause of the burning of 14,000 acres of forest within a mere 38 minutes during which 22 hunters and 6 dogs lost their lives. Known as "The Inferno of '66", it contributed to a widespread fear of loganberry trees and also to a fear of chopping those trees down. (The reader may take note that the alarmingly quick speed and high death tolls were due to the forest being almost entirely composed of loganberry trees)
In 1608, around 200 years after their discovery in Germany, loganberry trees were found in the Americas in what is now northern Virginia. The Native Americans currently living there called the loganberry n'galeth, or "power-giver". In their society, loganberries were used as fire fuel for rituals, and were believed to house the essence of life itself. As described above, 58 years later, loganberries would be shown to be the most destructive natural force that existed in the wild without engineering.
The Puritanical society of the time believed that the fruit brought destruction and chaos. As they were prone to regard anything with destructive power as Satanic, the berries became known as "devil-fruits", "Satan's turds", and, after the Inferno of '66, the "Terror of the New World". The Puritans hated the berry, and so did the Native Americans, but the only thing you should learn from this is that Robin is a big fat liar and he made this whole thing up.