Tannin is the name of a demon or dragon in Jewish mythology.
Etymology
The name developed in modern Hebrew Tannin (תנין) literally means crocodile or monitor, because the spirit monitors the individual in case of disobedience to the almighty.
Description
Tannin is represented as a dragon or a serpent.
Origin
Sometimes he is compared with Rahab, who is especially associated with the Red Sea. Some scholars associated Tannin with Tiamat, as it happened with asaszarim.
It is unclear in Jewish literature the differentiation between Tannin, Rahab and Leviathan, but Tannin and Rahab are more easily confused one with the other.
Tannin, as well as Rahab, was a name applied to Egypt after the exodus of the Israelites from that country.
In addition to the plagues of Egypt which were promised to be attached for disobeying the commands of the Almighty, Duet.28:15 give a greater understanding of the origin and mission of this spirit.
Also. I Samuel 16:14 and Judges 9:23