Isaac Asimov's Worlds of Fantasy. Book 6: Mythical Beasties

Kragen

The sea is a natural repository of enormous beasts, since the buoyancy of water largely neutralizes gravity. The blue whale with a top mark of 150 tons is far larger than any land creature thai ever lived; larger even than the largest dinosaurs.

Furthermore, water, in depths greater than a few yards, is opaque, so who knows what might be hidden in the deep. Even today, the relatively small Loch Ness in Scotland is thought to harbor a "monster," while the ocean itself is supposed to contain "sea serpents" of all kinds.

The Norwegians had legends of an enormous sea monster they called the kraken (is this another form of the Greek drakon? / wonder). It was pictured as an enormous round creature, possibly a mile and a half in circumference. To its rim were attached long tentacles, with which it could seize and pull under even the largest ships. When it submerged suddenly, it left a whirlpool in its wake, and sometimes whirlpools themselves were referred to as krakens.

In 1752, a Norwegian bishop, Erik Pontoppidan, published a Natural History of Norway in which the kraken was popularized.

There may be a germ of truth in even the wildest legend, however. The kraken sounds tike a large and monstrous octopus, and. indeed, in recent times the "giant squid" had been discovered. It does not normally come to the surface but it is the preferred food of the sperm whale, and dying squid that have had a fight with a sperm whale come to the surface on occasion. They are far, far smaller than the kraken, but one must allow for the exaggerations of legend.

In the following story, we have a large sea monster. It is not a giant squid. It is, rather, extraterrestrial, but the author indicates its conceptual origin in its name. which is almost kraken.