Continuing since it seems I reached the word limit for a post o-o

For Aliens from Hitchhiker's guide to the Galaxy, I take note that in the beginning of the book, Frank mentions that some teenager aliens would have joyrides abducting humans and putting them through the classic alien abduction senario, then just dump the humans back all the while laughing. This specific moment is the aliens pulling pranks. Many types of social creatures pull pranks, for example Chimpanzees and Gorillas in zoos have pulled pranks on each other and humans. Humans pull pranks on each other and other animals. So it could be argued that aliens could pull the whole abduction thing as a prank because that's a thing social creatures do. Aside from the silliness that point brings, the whole book has a wide variety of differnt types of aliens and has robots as part of the possible types of aliens out there. And inspite of the book being a comedy, there are moments where theres logical question to arise from the situations. For example, one planet has has the crazy thing of needing to have a mass recipt if you poop because of the tourism leading to a loss of resouces for the whole planet. The premise is absurd, but there are real ramifications of loss of mass from planets. We can see the small scale result of that in tourist towns with tourist taking the local rocks and fauna as souvenirs so it'll be even more of a problem of a tourism planet. So inspite of the clear comedy from the book, there are points that it shows just how diverse alien life can be.

For the Tripod aliens from War of the Worlds, this case is probably on the realisticly terrifying side. I am not refering to how those aliens were destroyed by an Earth borne disease. (The cold co-evolved with humanity so unless the same coevolution happened with the aliens, that plot is moot) No, what is terrifying is that those aliens are after resouces and they do not care how they get it. Humanity as a social species already does those things. Take the UK and imperialism for one. Chimpanzees will raid other clans for females and resources. So with my belief that interstellar aliens are a social species, the case for alien invasion for resources has a pretty high probability. Those rare spottings of UFO's scouts are for how to best take on the native life with the lease amount of effort.

Now for the Engineers and Aliens from the Alien movies. This one I am not a fan of because the lore has it that the Engineers are the proprietors of humanity. I personally like that humans have done things all on their own inspite of all the things just on Earth that could lead to our extinction. Humans are freaking awesome for getting into space in a span of 200,000 years. The Engineers as proprietors for life on Earth feels more like we are the experiments by aliens and the ocasional UFO sighting are from the Engineers checking up on their experiment. I may not like this case for alien life, but it does hold one thing that most accepted as true: life propegates life. Now there has been experiments of making the earliest lipid membranes ,(the cell membrane) with non organic materials. Though the results have not been fully accepted because one of the materials came from a dog and that throws the experiment off, even though non organic matter technically is still inorganic enen after getting in contact with organic matter.

Now for the actual aliens from the movie Alien. This case is the reverse, where humans are the ones to make first contact with the aliens. (I'm basing this just off the first movie for the sake of argument. Later entries made the alien as an artificial creation and made it more lame in my opinion.) So for the alien, it is an apex predator that humanity found. We can see that is is more solitary than the other aliens, so would that mean that my theory is wrong about aliens needing to be social? No because parasites are the exeption to the rule. With the way how The Alien reproduces, it employes a facehugger to latch onto a host. That host would suffer as a result of the face hugger turning into a chest burster. Now scientifically that works out, because humans are new to the parasite. For normal parasites, they do their best to not kill the host because a dead host means that the parasite needs to find another to keep reproducing, but there is no guarantee tk find another. With a new parasite to host interaction, the new host suffers because the parasite was supposed to find a different host that it coevolved with for a mutual benefit. Now the Alien is slightly different for becoming independant after exiting the host quite violently, but that's the beauty of alien biology, who knows if the original host species was able to survive that and they depended on each other. Speaking of original host, the way how the Alien has such a complex reproductive lifesycle that involves parasitiam, that means that there is proof of other alien life. Parasitism by definition requires two species. So that opened up the whole world of the Alien franchise, but they went the lame way of having humanity and the Alien be artificial creations. That's why this is not my favorite theory. The bioligy for how things evolved insependently is very fasinating, but the second artifical help is applied it really closes the world building of the series.

This may sound like a tangent, but I promise it does relate back to the Alien. Cuckoos are well know brood parasites. They lay their eggs in the nest of unsuspecting birds and rely on them to take care of their young. Well, evolution has it so that the host birds develop their ability to differentiate which is their eggs and which are a fake. And so in responce, the Cuckoo evolve their eggs to better blend in with the host egg. Its an evolutionary arms race. Well as the cuckoo spreads it's range of habitation, there will be signs in the other birds that they have encountered the cuckoo. There are birds that are very viligant in telling which is their eggs and which is not their egg. However in modern day, the cuckoo does not parisitize their nests at all, so why would those birds have such a keen eye for differentiating real and fake eggs? Because those birds won the arms race with the cuckoo. Eventhough cuckoos no longer parasite those nests, those birds still carry on the ability to differentiate real and fake eggs because they were forced to evolve to combat the cuckoos.

Now relating this back to the Alien, the Alien is a case where they have won the evolutionary arms race against their host species. And so the Aliens carry their adaptations from surviving their previous host species and adaptability to new ones. Now, here's an interesting point, why would I mention coevolution of a host species earlier, but say that the Alien won it's evolutionary arms race now? Well because both cases could be true. If the Alien chest bursting resulted from incompatible biology, then that explains why humans have it so rough with the Alien because we are not supposed to be the host. The original host species could have out adapted the Alien and won, so the Alien has to now find a new host. So there could be another alien species out there that has perfectly adapted to fighting the Alien.

But the second explanation works too because of the stasis of the Alien eggs for long periods of time. If the Alien won the arms race with many other alien species then they would need to adapt to needing to wait for the next host species to evolve and meet it. So that's where the eggs come in. Those Alien eggs are adapted to staying around until a sutible host evolved enough to find them and that's how the Alien propagates as a species by taking advantage of other alien specie's social tendency of not wanting their own to die. BUT NOOOOO we don't get cool stuff like this in sequel movies because the Engineers made humans and the Alien. Natural evolution has cooler stuff than artificial evolution

I hope that this is more in line with what you would like to explore in terms of aliens and alien life. Probably more a tangent to the Government anouncing info about aliens. But I really like when science can be used to prove interesting cases. Like for example, Interstellar gave us a theoretical look at what a black hole would look like and the real life picture, in low definition, does resemble the theoretical image they created for the movie. For me I would love to prove aliens exist, and theoretically there are cases which it can be true. Real life is stranger than fiction, so using science actually would stregthen the existance of aliens if there's enough evidence.