As far as our current “understanding” of reality— everything we know about it comes from 200 equations by James Maxwell Clerk, only caveat is the an uneducated man name Heavyside threw out all but four since they were, in his words, “impossible”, changing the four from field to vector equations... no one has ever bothered to reexamine them since 1875.
These "so called" aliens have specific behavior patterns and their interactions with humans always seem objective-oriented...and that objective, whatever it is, has to do with human reproduction and sexuality.
Many abductees (they are abducted over a lifetime) seem to fall prey to what we call "Stockholm Syndrome." But, before they begin to identify with their abductors, they describe them with powerful and consistent adjectives.
Some call them "evil" (I leave that to your imagination as to why they choose that term)...and some call them demonic. But everyone, at one time or another, says they (the aliens) are "liars"!
BTW, Whitney Strieber (an avowed atheist) in Communion said that when he was first abducted (actually the first time he, as an adult, remembered being abducted), he felt that, when in the presence of the "aliens," he was in the presence of profound evil!