The black and white patched cat was supposedly owned by an unknown crewman of the German battleship "Bismarck" and was on board the ship on 18 May 1941 when he set sail on Operation "Rheinübung" (German for Rhine Exercise), "Bismarck"s only mission. "Bismarck" was sunk after a fierce sea-battle on 27 May, from which only 114 from her crew of over 2,100, survived. Hours later, Oscar was found floating on a board and picked from the water by the British destroyer HMS "Cossack". Unaware of what his name had been on "Bismarck", the crew of "Cossack" named their new mascot "Oscar".