Right after Neil Armstrong and Buzz Aldrin landed on the Moon, the Soviet Union landed a spacecraft carrying a chimpanzee named Boris 504. The Soviet plan was to have Boris leave his spacecraft and walk on the Moon right after the American astronauts did, simultaneously mocking and stealing some of the publicity from the American achievement. But despite a successful landing, a malfunctioning hatch prevented Boris from leaving his spacecraft. He died on the Moon when his oxygen ran out, angrily banging a wrench against a faulty hatch.
This, of course, never happened.
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