(this is a story I posted on r/HFY, "HFY" being short for "Humanity F*** Yeah!", enjoy)

Journal entry #1, Cycle 0
Bipedal Specimen #1, hereto known as "The Specimen", has regained consciousness, after briefly exhibiting confusion and alarm over its unfamiliar surroundings, the Specimen calmed down surprisingly quickly. The Specimen's initial reaction to me as I entered its domicile to bring sustenance was that of brief alarm, followed by what appears to have been a moment of revulsion as the Specimen took note of me with its senses, which the Specimen then attempted to suppress before commanding its body to convey welcoming and friendliness while making gestures which appear to be intended to signal absence of hostile intentions. The Specimen accepted the offered sustenance and made sounds while gesturing at itself before making more sounds and gesturing at me, it is my professional opinion that the Specimen tried to communicate its name to me before asking for my name. Due to our vocal chords and auditory sensors functioning in vastly different ranges of wavelengths it is highly unlikely that either side acquired anything of value from our attempts at auditory communication.
Initial conclusions: The Specimen is confirmed to be not only sentient, but also civilized. Our scans of the Specimen's condition during its unconsciousness suggests its body is deteriorating, we shall try to prevent its death.

Journal entry #2, Cycle 4
The Specimen has adjusted to a consistent cycle of rest and activity, its body mass has ceased decreasing, whether it is due to changes in sustenance, atmospheric pressure, gravitational force, chemical composition of the atmosphere or the temperature inside the domicile, some unknown variable or a combination thereof, remains to be seen. Incremental increases in sustenance levels continue.

Added conclusions: The Specimen exhibits high adaptability to changes in its environment, multi-spectral scans of the Specimen show no recognizable signs of agitation so far.

Journal entry #3, Cycle 14
I Fear we may have made a mistake, for the past 10 cycles the Specimen has settled into a cycle of rest, physical exercise and making sounds while alone in the domicile, my colleagues suspect mental health degradation, but I believe the Specimen is in fact trying to entertain itself in the absence of external stimuli, the Specimen's muscle mass is growing at an alarming rate, our projections show the Specimen will be able to overpower our security personnel at will within the next five cycles.

Conclusions: contrary to initial beliefs Specimen has proven to be carnivorous, it is also highly intelligent & considering its adaptability, the speed at which its body repairs cellular damage & the rate at which it is able to increase muscle mass with the sustenance it is provided with, it is highly probable that this species initially started as prey, but the condition of the Specimen in particular upon discovery suggests absence of superior predators in the Specimen's life so far, indicating the Specimen represents the apex predator of its natural habitats.

Journal entry #4, Cycle 30
We didn't make a mistake, we made several. The Specimen's adaptability is far greater than we had anticipated, my idiot of an assistant accidentally doubled the gravity in the domicile, reduced temperature by 50 Qorkels & increased atmospheric pressure by three, and aside from the effects of decompression, the Specimen was virtually unaffected even after my assistant compounded his mistake by restoring the previous conditions instantly rather than gradually, the Specimen's ability to recover from the damage to internal organs (especially blood vessels-) caused by the rapid decompression is far greater than we thought, and the Specimen seems to be aware of exactly what was done to its domicile, the brief suspicion and hostility afterwards has caused my team to categorically refuse to proceed with the scheduled immunological experiments due to concerns over what the Specimen would do after inevitably making a full recovery from the infectious diseases.

Conclusion: it is my team's unanimous opinion that all possible resources should be dedicated to learning the Specimen's language so we can apologize to it & find out where it came from so that we can return it to its kind, hoping they won't mistake our actions for deliberate torture.

Captain's log, Expedition to return "The Specimen" to its World
We reached the Specimen't home world, which they apparently call "Ground" or something to that effect. I have both good news and terrible news.

Good news first: The Specimen's species is a Class 4 space faring civilization; they have orbital habitats for scientific research & their home world's orbit is saturated with artificial satellites, but they have yet to colonize other celestial bodies, they already have very rudimentary technology for colonizing their planet's natural satellite & are a generation (15, maybe 20 orbits around their star-) away from colonizing said natural satellite, by so doing becoming a Class 3 civilization, as such their kind doesn't pose an immediate threat to the Galactic civilization.

Terrible news: it has been barely ten generations since they started using electricity & they have already developed both fission- AND fusion-based weapons, and that was FIVE generations ago, AND the first thing they did after developing the fission device was to use it against their own kind, TWICE, in a war that was less than one orbit away from ending anyway. They started reducing their fission- and fusion weapon stockpiles three generations ago, but recent political developments between their nations (of which there are approximately 200, I say "approximately" because even they themselves can't agree on how many nations they have divided themselves into-) are likely to start a new buildup of these weapons, they have agreed to ban chemical and biological weapons from warfare which is promising, but then again they have ALSO agreed not to build more fission- and/or fusion weapons & are building them regardless so I remain skeptical.

Conclusion: we have to either quarantine the entire system to prevent them acquiring FTL technology OR glass their planet before they start colonizing Sol-4, their name for the planet closest to their own.

ADDENDUM BY GALACTIC ADMIRALTY: What the Captain of the Expedition failed to disclose in his log was the fact that the species of "The Specimen", hereby dubbed "Terrans", has a reproductive rate akin to vermin & that their home world Sol-3, dubbed "Terra", is approaching an unsustainable population growth, which is all but guaranteed to make the colonization of the natural satellite of their planet, "Luna", as well as Sol-4, "Mars", a primary concern in the near future, the fact that the Expedition has now revealed the existence of a Galactic community to them is expected to only add to the urgency of developing technologies to facilitate expansion beyond Sol-3.

The history of their species is rich with examples of explosive development of new technologies whenever potential outside threats appear, as such the fact that they have now made First Contact will most certainly cause the multitude of nations of Sol-3 to commit ever increasing resources to the colonization of the rest of the Sol system, even if just to make sure *they* can establish successful colonies on other celestial bodies before anyone else.