As all good persons will be aware I, Captain Sir Martin Frobisher, am the discoverer of the Alicorn or Narwhal. It is, therefore quite fortuitous that you would ask me about them.
I first discovered the narwhal on my second voyage to the New World in search of the Straight of Anean in 1577. The body of one of the whales had washed onto the shore of Frisland and looked as though it had been drowned some time. We were first attracted to the single, spiraling, pearlescent horn which protrudes from the forehead of the beast. We know, of course, that only one creature in nature is so adorned. I knew it immediately to be a unicorn. As it happens, we now know that these equine beasts can transmogrify themselves into great fish; seemingly for protection from hunters. This also explains why so few are seen upon the land in our modern age as it seems they have fewer predators under the sea.
After some discussion I procured a saw from our goods and removed the horn from this great drowned beast as a gift to our great patroness, Her Majesty Queen Elizabeth. It hangs in Windsor Castle and I understand her majesty has been known to use it's magical properties regularly to protect herself from Spanish poisons. I am greatly pleased that even whilst I am away at sea I may have a hand in protecting her majesty's person.
After much study afterward I can tell you that Narwhals are great blubbery magical whales native to the Arctic waters around Greenland, Frisland and the mouth of the aforementioned Straight of Anean. They are smaller than most whales of the North which betrays their magical nature and alternate form.
We know that unicorns have a knowledge of our human jousting and it has become clear that while in this fishy form they engage in the sport. Some of the sailors witnessed the beasts tilting while we sailed between Frisland and Queen Elizabeth's Foreland.
So blubberous are these whales that when I alerted the natives to them they quickly began to hunt the beasts with great skill and enthusiasm. They harvest almost all of the animal in a most impressive way.
The Inuit people of Meta Incognita began to refer to the raw blubber and skin as "mattak", a flattering mispronunciation of my first name. They seem to consider it a delicacy. Personally, I find the dish turns my stomach.
This is all we know of the Narwhal though I expect once we have found the ideal time of year to traverse the Straight of Anean from Frobisher Bay to the Pacific Ocean and Cathay many more expeditions may be made to study these creatures. Perhaps their greatest colonies lie in the middle of Meta Incognita and it is here that they frolic most often in equine form.