What is the largest living organism on Earth?

The largest living organism on Earth is a fungus in the Malheur National Forest in Oregon, USA. Armillaria ostoyae covers an area of over 2,400 acres (970 hectares), making it the largest known organism by area. It is a type of honey fungus that spreads through underground mycelia, a network of thread-like structures. Despite being largely hidden, this organism is connected through its roots, making it a single organism capable of living for thousands of years.