“Oh, so you guys actually fly Flying Saucers?”
“Yes, it’s the most efficient design for faster than light travel.”
“Okay, so what is up with all the probing?”
“That’s just how we greet people.”
“Oh… Yeah FYI that has a bit of a different connotation in human culture.”
Would be much more terrifying if the aliens actually acted like those grey aliens from the stories.
The version of aliens I found most terrifying are those that are actually far too human. Or, they are at least willing to treat us the way we’ve treated other creatures and other humans at times.
The most terrifying aliens are those that simply, at a fundamental level, do not recognize us as people. Whatever their definition of personhood is, we’re not part of it. Our pain means nothing. Our destruction means nothing. Our suffering means nothing. They’ll perform medical experiments on or disect someone alive without anesthesia, simply because they consider us no more worthy of personhood than we would consider rocks and trees worthy of it. To them, we are only collections of atoms, and we have zero moral value or agency.
Imagine being at the mercy of a being that has access to God like technology, but simply does not believe you have any moral value. Imagine a being that would happily and calmly flay you alive and afterwards honestly believe that they have done nothing wrong.
To me, that is the scariest kind of alien. One that treats humans exactly how we often treat other creatures.
There’s a good novel called Translation State by Ann Leckie you should read.
Technically you should read the Imperial Radch trilogy first since that establishes a lot of back story, but it features a species called the Presger who don’t even seem to conform to euclidean space, so much so any human who ends up in close proximity to them is assumed dead, even if they show back up looking fine, it is assumed they are a facsimile created by the Presger.
Horror movies use this fear so often. The Texas Chainsaw Massacre especially.
The book Under the Skin is directly related to this concept
Like the Qu except they believe it to be a moral imperative to do what they do. That answer to a higher power or purpose makes them more dangerous. They evolve species against their will and deform them horrifically to their image of what the universe should be and a lot of times it ends up in the eventual extinction or a torturous existence. Swriously fuck those things
The Mi-Go of the Lovecraft Mythos are basically that (via the CoC and DG games, which are kinda the main form of the modern Mythos). They are interested in the adaptations of terrestrial life to the exotic pocket of “not insane horror space” it occupies. Humans are an important part of that, but they aren’t people - nothing in earth-space can be people, due to it being sheltered from “actual” reality.
Though they’re willing to accept those who are infected with cosmic spores/etc and attain spooky enlightenment… but they’re probably going to be dissected as well, just willingly.