Rust Crabs

In the treacherous platforms of the Rusted Sea, a lone shape skitters along a shattered girder. From a distance, it seems like a walking oven, with six chitinous grey legs beneath a superheated metal box. Upon closer inspection, one can see eyestalks protruding from the front of the creature, swiveling back and forth to rapidly estimate what new danger approaches.
This is a rust crab, native to the Rusted Sea. It is unknown whether these are mechanical or biological in nature, but they seem to take their sustenance from the intense heat of the industrial-strength forges once common in the Sea. They will spend most of their time inside such forges in a state similar to sleep.
However, the forges no longer have all the proper machinery to keep them operated. Within the first year after the plant invasion, supply lines broke and fuel was no longer so readily available. So without some ingenuity on the part of the rust crab, they would never have the life-giving heat of the forges.
To solve this problem, the rust crabs venture out into the Rusted Sea to find the parts needed to maintain the forges and keep them running. So they do not cool to potentially fatal temperatures, they construct shells out of scrap metal and forge parts that strongly resemble the ovens in other parts of Verdure.
Regrettably, rust crabs are dying out. As they collect all the nearby parts that can be used to maintain their forges, they are forced to venture further and further afield through the hazardous territory of the Rusted Sea. Tragic falls through the crumbling platforms are common, and their shell-ovens are less and less reliable the longer the rust crabs journey.
Conservation efforts from Autumnal have succeeded in capturing several, but they are very difficult to keep alive in captivity. Without further intervention, the story of the rust crabs may come to an unfortunate end.