Here There Be Monsters

Columbus Day brings to mind all the various explorers who are more deserving of modern recognition than the dour Genoan you either love or loathe. One such admirable icon is our namesake, St. Brendan, who allegedly sailed across the Atlantic Ocean in the sixth century A.D. True, there is zero physical evidence to prove that this voyage actually occurred, though it does seem feasible based on the maritime technology of the day. But even if it's all a lie, you have to love the strange adventures that St. Brendan's chroniclers cooked up—I am fairly certain that Christopher Columbus never mistakenly alighted upon a giant fish:

At last they went upon an island weening to them that they had been safe, and made thereon a fire for to dress their dinner, but S. Brandon abode still in the ship, and when the fire was right hot and the meat nigh sodden, then this island began to move, whereof the monks were afeard, and fled anon to ship and left the fire and meat behind them, and marvelled sore of the moving. And S. Brandon comforted them and said it was a great fish named Jasconius, which laboreth night and day to put his tail in his mouth, but for greatness he may not.

There are obviously elements here of Jonah and the whale, as well as the Ouroboros. I'd also like to think that the good folks behind The Empire Strikes Back had this anecdote in mind when they cooked up that setpiece about the Exogorth.