In 1938, the Soviets requested a buffer zone in Finland because they expected the Nazis to attack through the country, yet the Finns resisted and maintained they were neutral. In November of 1939, the Red Army attacked Finland to get what they wanted. The result was the Winter War.
In the municipality of Rautjärvi near the Soviet/Finnish border, 34-year-old Simo Häyhä was a farmer and hunter leading a flagrantly unexciting life. Upon news of the hostilities, he gathered up food, plain white camouflage, and his iron-sighted SAKO M/28-30--a variant of the Soviet Mosin-Nagant rifle--and went to defend his country. Before the four-month war ended, humble Häyhä would gain infamy among the Russian invaders, and come to be known as the "White Death."
Read about how Häyhä achieved 505 confirmed kills in a war that lasted a little over three months before he was shot, and the fearsome legend that grew up around him, at Damn Interesting.