A cat nicknamed "Unsinkable Sam" survived the sinking of three separate ships during WW2.
Unsinkable Sam (also known as Oskar or Oscar) is the nickname of a real cat, reportedly in service as a ship's cat during World War II both in the Kriegsmarine and the Royal Navy, surviving the sinking of three ships in total.
The cat's original name is unknown. The name "Oscar" was given by the crew of the British destroyer HMS Cossack that rescued him from the sea following the sinking of the German battleship Bismarck. "Oscar" was derived from the International Code of Signals for the letter 'O', which is code for "Man Overboard"