The Wandering Isle - from concept to completion

I just finished this guy up for the Big Huge Concept Challenge over at www.gameartisans.org
Concept Description:
The Wandering Isle (or isles) is a giant ocean dwelling crustacean. Their exact origins are unknown; partly resembling crab, tortoise, octopus, and human, tales of these creatures have been cause for both astonishment and skepticism. Rarely seen above water, the wandering isle spends the majority of its life submerged along ocean coastlines. Unable to freely swim or walk on land (because of the gross weight of their shells) wandering isles skirt coastlines at depths that best allow them to buoy the weight of their shells and ease their burden.

Wandering isles are communal creatures and travel in family groups of 15 - 30 island pods. Because of their sheer size and longevity (the average life cycle of a wandering isle lasts for 1,000 years) small communities of humans have been known to make residence upon their backs. Furthermore, the communal nature of wandering isles allows entire island communities to form among the network of shifting isles as they plod through the shallow seas.

Wandering isles reproduce asexually but their nesting habits are similar to those of sea turtles. Near the end of its life, a wandering isle will head to shallow waters and then to dry land. The trip inland is disturbing for any passengers as well as for the wandering isle, since the further out of water it travels the more it must bear the full weight of its island shell. The wandering isle staggers inland until it collapses under its full weight and dies. This event is rarely witnessed, but long lines of wandering isle communities revere this process and flee their dying island in a ceremony of mourning and a celebration of new life. Weeks after the wandering isle has fallen to the earth, hatchling isles break free from their parent's shell and head for the sea.