Well, no, not the Ziz, the Leviathan, which I seem to have drawn like a hand puppet. I didn't set out to do that, but I think it's a good look. Classical sources describe the Leviathan as more serpenty than whaley. One legend says that God created a male and female Leviathan, but then thought better of it and killed the female so there would only ever be one. They'll both be served up to the righteous at the great feast at the end of the world, along with the Behomoth and Ziz. (Ziz appears to be female, as it lays eggs, one of which once broke and flooded sixty cities.)
In Job 41 God describes Leviathan to Job in rather scornful detail:
Who can open the doors of his face? his teeth are terrible round about.
His scales are his pride, shut up together as with a close seal.
One is so near to another, that no air can come between them.
They are joined one to another, they stick together, that they cannot be sundered.
By his neesings [sneezing or snorting] a light doth shine, and his eyes are like the eyelids of the morning.
Out of his mouth go burning lamps, and sparks of fire leap out.
Out of his nostrils goeth smoke, as out of a seething pot or caldron.
His breath kindleth coals, and a flame goeth out of his mouth.
In his neck remaineth strength, and sorrow is turned into joy before him.
The flakes of his flesh are joined together: they are firm in themselves; they cannot be moved.
His heart is as firm as a stone; yea, as hard as a piece of the nether millstone....
Sharp stones are under him: he spreadeth sharp pointed things upon the mire.
The eyelids of the morning! That's King James, of course, which is usually the most poetic translation, and so is the one I generally use, but I have to admit that the New International Version is more accessible in this instance:
Who dares open the doors of his mouth, ringed about with his fearsome teeth?
His back has rows of shields tightly sealed together;
Each is so close to the next that no air can pass between.
They are joined fast to one another; they cling together and cannot be parted.
His snorting throws out flashes of light; his eyes are like the rays of dawn.
Firebrands stream from his mouth; sparks of fire shoot out.
Smoke pours from his nostrils as from a boiling pot over a fire of reeds.
His breath sets coals ablaze, and flames dart from his mouth.
Strength resides in his neck; dismay goes before him.
The folds of his flesh are tightly joined; they are firm and immovable.
His chest is hard as rock, hard as a lower millstone....
His undersides are jagged potsherds, leaving a trail in the mud like a threshing-sledge.
So, you know, I drew him as a hand puppet. A hand puppet with eyes like the eyelids of the morning, mind you -- which means Leviathan is shining light out of its eyes, and the great fish is shining light out of its window-eyes from the big glowing pearl suspended inside it, and just imagine these eyebeams cutting through the blackness of tehom, the primal waters from before Creation that are older than light itself because they were there before God first spoke, which Jonah 2:5 says he has descended into: "the depth closed me round about" is the rather pallid KJV translation of this idea that Jonah has actually kind of gone backward in time to before Creation, like God said, "You want to run away? OK, I'll just put you in tehom before I even showed up and you can just sit there and wonder if I ever will or if you'll be all alone in the abode of the dead forever, mister." What an appalling idea, reminiscent of childhood and all its terrors of abandonment and loss -- and Jonah is in a womb again, so he's gone backward in time that way too. No wonder Rabbi Meir made up that thing about the pearl, it's kind of hard even to think about Jonah stuck in tehom for three days and nights without any light at all. He might even have been glad to see Leviathan, and the toothy doors of his face.