LEVIATHAN

 
Possibly a crocodile
Job 41.
There go the ships: there is that leviathan, whom thou hast made to play therein. (Psalm 104:2626There go the ships: there is that leviathan, whom thou hast made to play therein. (Psalm 104:26))
"The crooked (R. V.) serpent."
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 27:11In 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))
FIGURATIVE
Thou brakest the heads of leviathan in pieces, and gavest him to be meat to the people inhabiting the wilderness. (Psalm 74:1414Thou brakest the heads of leviathan in pieces, and gavest him to be meat to the people inhabiting the wilderness. (Psalm 74:14))