Rethin
a metal which is molten at relatively low temperatures, it forms the core of the planet Bespin, and is mined for various uses. At slightly higher temperatures, rethin melts and eventually dissipates as a gas. It is very light in its gaseous form, and rethin is consumed by the beldons of Bespin to help them remain bouyant and float. The beldons then produce tibanna gas as a waste product. The unique space beldon, however, can produce its own rethin by digesting the interstellar gases of nebulae and gas clouds.