TON 618 is a supermassive black hole with an estimated mass of 66 billion times that of the Sun. It is one of the most massive black holes ever discovered and is located at the center of a distant quasar, approximately 10.4 billion light-years away. Its mass is so great that it exceeds the combined mass of all the stars in our Milky Way galaxy. Its enormous size has led astronomers to classify it as an "ultra-massive" black hole. TON 618 is the engine of a highly luminous quasar, meaning the bla