It may look ordinary, but it's the most powerful bean of all of Center Earth.
According to Randalf, when the world was covered in snow a long time ago and where flobbits flanter in the shade, four beans were given to knights. Each with special powers. The first can grow any type of food, the second can change your appearnce (eg. height and hair), the third can give you clothing, and the final one can pop out kitchen appilances (eg. toasters, blenders). Unfortunately, the four chosen ones didn't know what they're meant to do, and cook them in stew. However, a fifth bean was made, which combines all the powers of the four foresaid beans.
It's unknown how many used the bean before, but as seen in the story, a total of three flobbits used it. The first was Ahem, who found it with the packing peanuts.