Some things I've noted so far. They emit particles and sounds similar to UA. The spikes yield Phosphorous, Nickel, Carbon, Iron, Manganese, Sulphur, Mercury, Arsenic, Germanium - seems they are "feeding" or at least composed of some of the stuff in the nebula. Also, they make some sort of "digging" type noise (best I can explain it) like there is movement undergound. My theory is we will find them in the yellowish sulphur areas. It seems to me that these areas are kind of like "riverbeds" and have had flowing liquid of some sort from geysers or volcanic activity in the past. I'm no scientist, just some thoughts I had.
Edit: also, I think they were onto something about the planet being far from the sun, as the melting point clue in the description mentions they probably dont like it too hot.