Gunpowder Wasps
Never allow the sophonts at the Galactic Uplift Bureau’s Surreptitious Assistance Department too much free time. Or access to trashy Old Earth vidshows, apparently. GUB-SAD operatives can get themselves into all sorts of trouble that way.
The basic problem is this: most oxygen-nitrogen water worlds in the Milky Way galaxy have roughly similar biospheres, and that’s not even remotely accidental. A standard biological package of photosynthetic bacteria was apparently introduced to every planet that looked like it could support it (don’t ask anybody in the various Galactic governments who, or Who, did that). So, you can introduce new species into a particular planetary mix. If you have that sort of mind.
And it takes a very special kind of mind to create the Gunpowder Wasp. Despite the name, it doesn’t have a stinger, but it definitely looks like a Terran wasp. A colony will produce ‘hives’ of long, hollow tubes made out of dried clay, which is mixed with a secretion from the wasp that turns it into a waterproof ceramic. Worse, the dung produced by the wasps is essentially gunpowder; with the right kind of filter paper, you can wash out the pipe and collect enough gunpowder in the filter for about three shots or so (once it’s dry). And — of course — the wasps helpfully anchor their pipes to each other using exactly that kind of paper.
In other words: a Gunpowder Wasp nest can be turned into 1d6 primitive firearms, with ammunition for a total of 3d6 shots (you’ll need to find suitable rocks yourself – no, wait, the Gunpowder Wasps prefer rocky areas for their nests). They’re exceedingly primitive, highly inaccurate at medium range, and possibly dangerous firearms, but they’ll work. It’s actually pretty easy to make one, too.
So why did GUB-SAD genetically engineer these things? Because watching primitive cultures spend forever trying to get to space flight on their own is boring, of course. So: give them access to organic firearms, and watch them zoom up the technological tree…