Behemoth

Larger than the largest three-point baleen, the white whale called Behemoth is one of the kings of the sea. The Behemoth has a single horn projecting from its blunt snout like a narwhal. Its teeth, however, are unlike those of other whales; each is over six feet long and razor sharp. The Behemoth's hide is studded with scars and several broken harpoons are still embedded in its back. It doesn't seem to notice them.

The Behemoth attacks from below. The only warning msot of its victims get is a flicker of movement in the water before its horn  bursts through their ship and the Behemoth begins to feast.