Less “Deathworld” and more “Underhive”, its some quick crystal formations today.
From Necromunda: Outlanders p.106:
Found at the edges of effluent pools, discharge outlets or any other place where pollutants are allowed to accumulate over an extended period of time, Spine Crystals are not in fact plants, but rather mineral growths. Similar to coral, they are made of densely packed crystals which while brittle, are razor sharp.
Anyone foolish enough or lost enough to find themselves in a growth of Spine Crystals will quickly regret it, as the splintered edges open thousands of tiny and extremely painful cuts. The greatest danger comes from the toxins and corrosive chemicals from which the crystals grow, and is passed into the wounds, turning the smallest scratch into a festering sore that can lead to death if untreated
These crystal markers are also suitable for use as other weird alien things, like the zombie creating Perilium that is mentioned in some Pulp Alley: Perilous Island scenarios or the chunks of Supermans home planet that regularly cause him so much grief.
I got the crystals from a gamer a while back. He was planning to use them to jazz up bases or similar I think. I dont know what sort of crystal they are or where they came from originally.
On a whim recently I glued a few of the crystals to some bases and quickly painted them with Tamiya Clear Green and ta-dah! Now they are objective/hazard markers. Thats another Alien Flora & Fauna project entry done, but this time from an entry in the Necromunda: Outlanders supplement. So it isnt really “flora” or “fauna” and it doesnt come from a “deathworld”. It is alien at least.