In a distant future, humanity has colonized and catalogued countless worlds in their home galaxy. However one day humanity has discovered a few habitable words in the Andromeda galaxy.

After a while of researching the planets ecosystems and wildlife, scientists have stumbled upon one creature that seems to warp its environment on a minuscule to drastic level.

The creature itself primarily lives in caves, and can eat rocks and metals but will sometimes go out in the open to eat both plants and animals. The creature hatches from an egg that seems to be composed out of a crystalline coating, and is, at birth, the size of a medium sized dog.

Scientists have seen that in the wild, if the creature is outmatches or startled, it’ll spray a mist like substance out of the sides of its body before darting away to a nearby cave. After a few minutes the area that has been sprayed with this mist like substance can start to be seen sprouting tiny crystal like formations, but after a few hours, the crystals will have grown in size, being estimated to grown to the size of doors. Luckily these crystalline formations will start to break down and later be blown away by the wind.

In caves however, the creatures seem to regularly spray this substance all over the cave walls, which can result in a very brittle yet beautiful place to explore. The scientist have theorized that these crystals, when sprayed in caves is a way for them to navigate and ensure safety, however, when out in the open it is assumed that this substance first acts like a irritant, but later will either crush the creature due to its weight or damage the creature, leaving injuries that are similar to slight burns and severe rashes.

Why would force a creature to evolve the ability to spray a substance that forms door sized crystals over a few hours?

  • $\begingroup$ User castlewrks wishes to note: See: en.wikipedia.org/wiki/The_Devil_in_the_Dark, one of the original Star Trek series. (added this comment so that nir input is not lost if their answer gets deleted for being a link-only answer) $\endgroup$
    – SRM
    Jan 30, 2020 at 6:32

2 Answers 2


Some desert lizard have evolved a pretty peculiar water saving adaptation: they concentrate their urine so much that the pee a crystal-like substance.

In this way they don't waste scarce and hardly gained water.

So, excreting crystal-like substances is feasible.

Then, if you have ever watched a footage of the pharaoh's serpent, more formally mercury(II) thiocyanate, you also know that dramatic expansion of the by-products of a chemical reaction is possible.

Thus, wrapping up, the trick is: secrete a substance in a crystal-like state, which then reacts with the environment to produce an expanding substance.


My immediate assumption would be that it could create shelter with those door-sized crystals. If this planet has particularly brutal weather (extreme heat, cold, or storms), being able to choke off the effect in a cave would be a huge benefit.

I'd also see a potential benefit for hunting. What if its prey is consistently faster than it, and it doesn't have any abilities to instantly incapacitate that prey? Spray it with this crystal mist. If the creature itself forms crystals over time, it can be tracked down and killed/digested more slowly-- almost like a spider's web, or a venom that slowly takes effect.

Speaking of-- what if the crystals function somewhat like saliva? You mentioned that they break down over time, and that it has a hugely varied diet. Maybe the crystals bond to some elements in its food and break it down into compounds that the creature can more readily digest/fit in its mouth when they dissolve?

Interesting creature idea. There's a decent chance I steal this thing for a DnD boss fight some day. :)


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