Strange Brew by John Deering 5/3

It is obvious, actually.
A Leviathan lives in the salt water, a Behemoth lives in fresh water.
Behemoth were monstrous hippos and Leviathan were monstrous whales.
More importantly, however, neither of them usually have tentacles.
Consequently, neither of them were that scary.

What you have there is a Kraken. Probably a Norwegian one. Though it could be the more dangerous B-Movie Kraken–a species whose population has dramatically increased in the last few years.