The sheer beauty of a burning fishman running about frantically almost makes up for when he wanders next to the gunpowder. Almost.
Leyden Pistols, grenade launchers, and Steam Knights are all weapons of chaos. Having them around guarantees a good time, especially if you keep high explosives near any expensive goods. If you want a safe, dull colony, you just don't build them. If you want an apocalypse, you do.
Somewhere I reported the history of a colony in which alcoholics, gunpowder and crop fields were next to each others. And then, my leyden-armed militia met a selenial casually wandering over the fields...
I think they are the glowing orbs and slugs that your colonist love to swat at, they kind of explode when "killed".
The Selenials are those strange spores (glowing or dormat) that usually come with a meteor shower event. They have an interesting life cycle, which, as far as I've seen, consists in 3 different stages (4 if you count in two different states of the spores). [Selenials around]+[Leyden weapons]=[Widespread fires]
Mayhap one could throw them at enemies, As throwing a small grenade.. You mean to say they can be found in a dormant stage that may be useful, if one had a tungsten bottle to contani the little ,tasty looking, dears. I do not suppose they should be used as a doormat.
If they have a use as dormant, I'm still not aware of it. I usually trade them: less danger and more goods I'm not really in a advanced (tech tree&co.) stage with this build, mainly because the Alpine colony really took me a lot of time and didn't go anywhere... The flying spores aren't dangerous because they explode, but because they fly around easily. And with layden weapons they catch on fire really easily. So you have a wandering source of fire. And guess what? Your crops are really flammable! Spoiler: to Exile I tried to send you a PM to reply on the "grammar post" but it seems I cannot start a conversation with you.