There's a 3 1/2-square mile specimen in eastern Oregon that weighs 35,000 tons and could possibly be the biggest living thing on Earth, according to researchers at the University of Utah. It caused $1.5 million worth of damage to Georgia's peach trees in only two years. Armillaria ostoyae - the scientific name of the fungus - infects and kills 600 different species of woody plants and it is very difficult to kill this fungus.