I've been wondering for years what exactly the creature described by GOD in the Book of Job chapter 41 is. Someone said it's a great crocodile. But on making my searches, crocodiles have scutes and not scales, this which we can say does not match the description of the leviathan.

In my findings, it was described to be a monstrous sea serpent, as the Bible also describes that it stays in the sea.

Psalms 104 (KJV)
¯¯¯¯¯¯¯¯¯¯
²⁴ O LORD, how manifold are thy works! in wisdom hast thou made them all: the earth is full of thy riches.
²⁵ So is this great and wide sea, wherein are things creeping innumerable, both small and great beasts.
²⁶ There go the ships: there is that leviathan, whom thou hast made to play therein.
²⁷ These wait all upon thee; that thou mayest give them their meat in due season.

Now, could it be that them of those days had encounters with this dreadful sea monster that they know what GOD described in Job 41?

And also, the Bible compares the Leviathan to a dreadful enemy that GOD alone can control, punish or kill.

“In that day the LORD with his sore and great and strong sword shall punish leviathan the piercing serpent, even leviathan that crooked serpent; and he shall slay the dragon that is in the sea.”
— Isaiah 27:1 (KJV)

For this indeed, makes us realize that this leviathan is a dreadful creature which scares or/and snaps the life out of humans, so GOD asked, if no man could stand before the leviathan, then who can stand before Him?

“None is so fierce that dare stir him up: who then is able to stand before me?”
— Job 41:10 (KJV)

Now, what exactly is the Leviathan?