See Monsters 2
There have been speculations, modern and ancient, about a very strange creature with wings and a human-like face that lives in the ocean. I’ve seen it called a “Bishop Fish” in medieval writings. I just read a 1400’s argument from one of my favorite mad scientists (Kircher) where he argued that they are cephalopods. It bears a striking resemblance to old Mesopotamian depictions of fish men, and some ancient descriptions of mer-men and selkies. The folds, clothing, robes, head whiskers, or wings all look suspiciously like the apendages of dead rays and skates.
Once when I was young, I was walking along the Atlantic ocean, where fishermen had long rods and chum buckets. When they caught the small skates that lived there, they would put them down on the beach, belly up. I can vividly remember the horror I felt when I saw what appeared to be cute pudgy human faces on their underbelly. I think this odd resemblance to a human face inspired third and fourth hand accounts from land lubbers who saw some kind of dead skate or ray. I’m fairly certain that this is the origin of the Bishop Fish, and not inaccurate sightings of octopi or cuttlefish as Kircher suggests.
Actual rays and skates, from what modern science tells us about them, are not a lot less weird than fantastic creatures of medieval bestiaries. They share some bizarre biological traits with the rest of shark family: Their bones are soft like cartilage, and they possess a sensory organ that is very rare for any creature on our planet. The long lateral surface of the “nose” that is so well developed in hammerheads and rays has tiny receptors that measure the electro-magnetic discharge of living creatures. This allows them to find hidden prey in sand, coral and sea plants. They possess other even weirder, diverse adaptations that no shark does. Some can produce strong electrical charges, many have spines on their tails, some of them are deadly poisonous… then there is the saw-bill: too ridiculous and improbable a creature to make it into the old bestiaries alongside wyverns and basilisks.
No, really, they’re weird as hell… check out this natural science page geared toward kids: http://www.flmnh.ufl.edu/fish/education/questions/raybasics.html
a dead ray, looking slightly upset. The creature’s actual eyes are on the other side, but the mouth is pretty much a mouth.