Shelkers are prolific, aquatic mechanoforms scuttling across the seabeds of the world’s oceans and the sunny beaches of its coasts. They stand out by being the most life-like of all mechanoforms, their painted metal bodies closely resembling a crab at first glance.
The first obvious giveaway that it’s a Shelker rather than a regular crab is the pair of cylindrical power coils, one visible on either side of the Shelker’s body. These appear to scavenge salt from the seawater and they are somehow able to process this into some source of energy. Just how they do that is unknown, and as with other mechanoforms the true nature of their origin and their purpose will likely never be fully understood.
A side effect of how these mechanical animals feed themselves is that they end up purifying the water they live in. As such, the coasts lucky enough to have populations of Shelkers usually have pristine waters, free of pollution and rarely experience algae blooms.
Other than that, Shelkers don’t contribute much to their local ecosystems. They don’t eat and aren’t eaten by anything, so while their presence improves their local environment immensely they aren’t an active part of the food web where they happen to exist.
Sometimes, Shelkers are caught by rigs trawling the open sea miles from the coast. It’s thought that they wander around, guided by some sort of sense, moving from place to place. This means that a spot that might’ve been known for its numerous Shelkers years ago might be deserted now, the only evidence of their former presence there being the rich, healthy waters they leave behind.