The Dunshar

In the 'nude', the Dunshar are just amorphous masses of jelly, moving around on gossamer-thin pseudopods, the only distinguishing features being several colorful eyes on stalks as well as two antennae, very sensitive to sound and smells.

Rarely do they remain in this state though. Being able to grow thin tendrils through mud, earth, stone or metal, they can animate it and use as a body to shield their fragile self.

The weakest and youngest individuals are able to animate only light soil and mud, and it takes rigorous training to proceed to dese eart and clay, or terracotta and brick. It takes a real feat of will to bring stone to life, and metal is beyond most of the species.

Once an individual makes a 'matter-transition', or Herar, as they call it, he can animate bodies of his 'new' matter with ease, but those he abandoned are forever beyond him - a Dunshar clad in steel will do with nothing less: stone and earth are dead to him.
Their bodies will be of two distinctive types: if he assembled it himself, the Dunshar will use his tendrils and will to shape the body to his liking over time - at first, he'll look like a mass of rubble. If he flowed into a ready statue, he'll have much less work to do.
Thus, wealthy Dunshar will order pre-made bodies from great artists, though some of them reject this practice as lazy and fit only for weaklings.
The size and number of appendages a Dunshar can control depend on his intellect and ability to concentrate. A stupid and distracted one will wear a body the size of a kid, with three or four legs to stabilize it, and one manipulative appendage. A wise one might be able to awaken a statue the size of a horse, and control six arms independently of each other.
This is no purely magical ability per se - the Dunshar truly grows through the entirety of the statue with myriads of tendrils and veins, and the special properties of his body make it malleable. If he wears a heap of rubble, it's his body that holds it together... they're quite strong, but easy to burn, cut, etc. when nude.
A Dunshar can only breed with those wearing the same or similar material as him - they will try to make spectacular and elegant bodies as to attract mates, compared to the more practical ones worn during everyday life.
Their society is structured along lines that come naturally - an able individual will don a better body, thus their representatives and rulers are elected from amongst the stone- and steelclad.

They place a great emphasis on learning and science, as well as the arts, supporting and encouraging scholars and artists to tend to but their pursuits, the state taking care of them.
Other races are likewise a subject of study for them, but the Dunshar themselves don't want to be seen nude, physically or metaphorically, thus they reveal little of their doings to foreigners, trying to appear distinguished and formidable, seldomly crossing inter-species borders.
Still, their glass- and crystal-clad emissaries, having shaped their body to the likeliness of the natives, are seen at many a court or parliament, representing their nation and studying the ways of the foreigners.