Leviathan

The Midrash considers Leviathan to be the most important of the three eschatological animals. Like the Ziz it is destined to be eaten by the righteous in paradise after the mortal combat in which it and Behemoth kill one another. So huge is Leviathan that its skin will be used by God to build tabernacles in which the most deserving among the righteous will sit to enjoy the meat of the three animals which the Midrash adds, are so pure that their meat is permitted, rewarding the righteous for denying themselves the pleasure of forbidden meat in this world.

Leviathan is depicted here as a big fish with scales and fins, its mouth full of sharp menacing teeth. Its body forms a loop, the tail nearly touching the head.