Small blue-white button mushrooms that rarely grow larger that two inches in diameter that release an electrical discharge when disturbed.  While one is a nuance, no more harmful than a static shock, however large colonies are known to be kill even large stock animals like horses and cows.  Left undisturbed bolts of energy will arc from cap to cap.  Ground into a fine powder and added to food Thunderleaf will produce a slight numbing tingle.  While hard to cultivate it can be used to grow traps.  Also known as Shocker Shroom.