>>17863109 (OP)"Little Boy" and "Fat Man" were the nicknames of the two atomic bombs used during World War II. "Little Boy", a uranium gun-type bomb, was dropped on Hiroshima on August 6, 1945. "Fat Man", a plutonium implosion-type bomb, was dropped on Nagasaki three days later. These bombings were pivotal in bringing about Japan's surrender and the end of World War II.