Karack metallite

Karack metallites were small burrowing creatures that consumed metal. In their dormant state they took on the appearance of six-sided borinium ingots, a form of currency. When awake, the metallites moved like spiders on six spindly black legs with red stripes. They could survive in atmosphere and, at least for a time, in vacuum. The only thing known to kill them was extreme heat, as in a fire.