<human>:  When did the Leviathan first appear in mythology?
<bot>: The Leviathan is a sea monster in the Book of Job in the Hebrew Bible. The name Leviathan is a combination of two Hebrew words: levi meaning "cub" or "young lion" and ath means "giant". The Leviathan is described as having a body like a cedar and a tail like a winding serpent. The Leviathan is sometimes said to be the ancestor of the sea dragon, which is mentioned in the Bible.