For as long as ships sailed the oceans, legends of collosal squid, large enough to drag ships to the bottom of the ocean, have existed. Similarly, for as long as LEGO fans have built ships, they have built creatures to battle with them - sea serpents, giant squid, sharks and other monstrosities. But most common by far is the Kraken, often inspired by popular fiction, such as the Pirates of the Caribbean movies.
The smooth, aquadynamic form of the Kraken, in particular the tentacles, poses a difficult problem when building with cuboid bricks. However, as the parts palette available to builders expands, the problem becomes easier to solve.
The simplest solution to the Kraken is provided by The LEGO Group themselves - an octopus. Although far smaller than most giant squid are imagined, when used with a smallish vessel, they offer a quick and easy solution, such as in 6240 Kraken Attackin' -
It is perhaps more effective when used in conjunction with a microscale ship, such as in Paul Cantu's MOC -
For those wanting a larger Kraken capable of mauling full-size ships, a brick-built alternative is necessary. The tentacles pose the greatest problem to builders, and a number of methods have evolved so far.
Again, the most wide-spread solution comes directly from LEGO themselves, in the form of the "tentacle system" - that is, the various parts that can be fitted together and posed to form tentacles, tails, trunks and the like. First released in 2001, it wasn't long before a giant squid appeared in a set, namely 4796 Ogel Mutant Squid -
A slightly more realistic squid came in 7775 Aquabase Invasion as part of the Aquaraiders theme in 2007, which soon became the basis for most brick-built squid -
However, given the Kraken's propensity to remain underwater, the body is often left un-built, and just the tentacles represented, such as in Hippotam's MOC, the Last Journey -
The length of tentacles that can be obtained using the "tentacle system" is, however, limited, and so other methods must be used if a larger Kraken is wanted.
The use of hinge bricks and plates allows for greater posing than using the "tentacle system", although it can be blockier. However, it allows for the use of 1x1 round plates to be used as suckers, such as in Josh Morris' MOC, Bones and Calamari -
Entirely brick-built tentacles have also been experimented with, such as in Indy Ram's MOC -
There have also been attempts to integrate the "tentacle system" with brick-built extensions, such as Paul Brassington's MOC -
Other less conventional techniques are emerging, for example SirNadroj's use of Creator monkey tails -
Other methods of tentacle-building out there, which haven't yet been applied to the building of giant squid, include the use of inverted rubber tyres, which gained prominence through the Black Fantasy genre, such as this MOC by Lt. De Martinet - imagine 8 of these on a collosal body!
10192 Space Skulls comes with enough black cylinder-hinges for nearly 2 giant squid!
The body is another problem for MOCers. It is commonly solved by brick-building or using slopes, as seen in examples above, or by using larger pre-fabricated curved elements, such as in Rod Gillies' Calamari Calamity -
However, it remains simpler and perhaps more effective to leave the body underwater, and just build the tentacles.
N.B. Although there are notable differences between giant squid, octopi and various renditions of the Kraken, for the purposes of this essay, they are all included as one and the same thing.
Update! It looks like the new Atlantis line comes with 2 different Kraken, one which appears to have a new tentacle piece! See more here
Look out for Building Sea Serpents soon!