can take inspiration from other stuff

Considering it’s from the book of Job, believed to be the oldest book in the Bible, it’s not out of the question that it might have referred to a mosasaurus or plesiosaur.

But both that and “behemoth” are two terms in that book whose strict definitions have been lost to our own imaginations.

according to Psalms 74:14, the leviathan was multi headed sea serpent but was killed by god

That Psalm is about questioning where God is in the present despite all the deeds He did in the past. When he brings up crushing heads of Leviathan, that’s just one of many things that’s being talked about. The verse before that said God split the seas with his might, which is a reference to Genesis.

But there isn’t a reference in the Bible for God literally slaying a multi-headed sea serpent. The Psalm isn’t retelling a Biblical story there, it’s using symbolism to show that God has overcome the chaos that’s infected the world.

But with that said, what I said about the reference in Job is merely a game theory.

a what theory...?