Expressed the 28th November 2022
On such planets hosting carbonated multi-cellular complex lifeforms, fungus such as Ophiocordyceps unilateralis (see here), commonly known as zombie-ant fungus (see below) — could have spread to all living organisms — like The Flood in Halo ?
There you can see what happens to infected ants. The fungus infect their nervous system to force them to get on top of trees before growing through their dead body to release new spores and infects other hosts (exclusively ants).
See a video from National Geographic there.
For this risk, a planet totally infected with such as parasitic fungus may not pose a real risk, for :
1️⃣ The low probabilities of two planets hosting carbonated life being relativistic near with one being home of an intelligent species able to move itself in the Universe.
2️⃣ The extremely low probabilities of an encounter of this parasite during the time frame of a adventurous exploration by the intelligent species, because of the physical limitations of pronation of such a parasite, meaning :
The natural limitation between viable hosts and predatory parasites (or Natural Regulation Principle).
The impossibility of such a parasite to leave its home planet, for in the extreme case of this happening to a intelligent species able to move itself in the Universe, a cure may be found really quickly.
3️⃣ Finally, the extremely low probabilities of a "biological perfect-match" between the parasite fungus and the newcomer — or the intelligent species arriving on this planet — for they are not baked in same planetary soup.
A couple of Astronauts lovers arrives on an infected planet (like described above), they begin to make scientific analysis of the local lifeforms and rapidly understand its parasitic potential — thus separating themselves in quarantine and exchanging through radio-communications. One of the partners rapidly gets the certainty that it is not biologically-compatible with them, whereas the other would not.
The one being sure that this isn't compatible would insist for them to reunite and break the quarantine, while the others strongly disagree. The disagreeing one would slowly become paranoid and assault him for the false belief that he may be infected with the parasite. The other one, taking time to get out to make explorations, also try to cure his paranoid partner and make her therapy because she do not get out anymore — paranoid, she thinks that the infection may also have psycho-cognitive effects on him and she then try to kill him through constant radio-communication harassment.
At the end, she kill herself while his partner is still trying to help her sort out what is true and false. He hear her suicide through the radio-communication system for they were still apart because she didn't want to break the quarantine.
After that, in a last pre-recorded automated message, she reveals all the conscious moments she had where she tells him that she loves him. the funny moments they managed to have despite the situation and all their shared joy about the discoveries from the planet.
