Largest Living Organism: Fungus world's largest organism Largest Living Organism: Fungus honey mushroom www.extremescience.com www.extremescience.com... Oregon 2,200 acres in size.) the largest living organism http://www.extremescience.com/biggest-living-thing.htm don’t get me started The largest living organism on the planet Largest Living Organism: Giant Honey Mushroom in Oregon Largest Living Organism: Fungus Largest Living Organism: Fungus