 This rather unassuming sphere is responsible for the deaths of two men, one accidental and one a little bit recklessly. It is known as the Demon Core, a 6.2 kilogram or 14 pound sub-critical mass of plutonium. It was made to be the core of an atomic bomb to be used on a third attack on Japan. This never came to fruition, so it was used for some experiments. The experiments were designed to show how close the core was to criticality but would end in tragedy for two men. Both men, who died, undertook experiments at different times. They were physicists Harry Daglian and Lewis Slottin. Both suffered acute radiation syndrome and died soon after in 1945 and 1946 respectively. Want to know more? Check out my full video on the subject.