Cyrus the Unsinkable Sea Serpent by Bill Peet tells the story of Cyrus, a monstrous sea serpent who was not at all fierce. When a shark challenges Cyrus for being a sissy because he doesn’t sink ships, Cyrus goes off in search of a ship to sink. Cyrus finds a ship, the Primrose, but instead of sinking it, Cyrus ends up following the ship and protecting it from many dangers on its ocean voyage.