Here's a possiblity:
Human consciousness plays out on the quantum level and creates a kind of energy that is "pan dimensional" (for lack of a better word). In our world it gives us self awareness and emotions, but it also spews out across the multiverse.
"Aliens" aren't aliens at all... they (as well as most ghosts) are parasitic entities from the "other side" of human consciousness that "feed" on that energy. It's impossible to accurately explain in human terms as it's totally outside human experience/comprehension but a kindergarten level explanation is that they're sort of like humanity's mirror image if our mirror image could think/act for itself but still needed us to look in the mirror to cast our reflection in the first place for them to even exist.
The actual bug-eyed beings and their UFOs are probes and "avatars" the "alien beings" uses to access, manipulate and travel within our reality.... tools and containers for the real consciousness behind them which cannot otherwise leave it's own "dimension" anymore than a human could enter their's.
Their goal is quite literally to farm us... to maintain our world as a place constantly producing "great tasting" energetic emotions of all flavors, to breed better (for them) varieties of "livestock" for their harvesting and to keep the farm safe from total destruction... and therefore reliably and productively producing energy for them in their own world.
To meet these ends they constantly manage, tweak, breed, cull and manipulate humanity through genetics, culture, religion, technological developments, conflict, art, ect. virtually every human endeavor you can think of.
They have been doing so for tens of thousands of years or maybe more. They are quite content to keep humanity perpetually in the dark, unable to spiritually progress into higher beings and occupy both benevolent and malevolent sides of the equation simultaneously... just like a human farmer if we were considering the farm from the animal's perspective.
Their worst fear is that humanity will "wake up" as each human conscious mind essentially a "shard of God's/Universal consciousness" and is orders of magnitude more powerful than the "aliens"... not to mention they are totally dependent on us for their very existence.
Another possibility is that we
are them... aliens could be future humans (or whatever humans evolved into) with god-like technological prowess. Perhaps we are plugged into an amazing quantum computer simulation of Earth and are having a "matrix" experience ourselves in a world that is
actually a replica of very ancient times.
Whether it's voluntary or not is anyone's guess but my first guess would be that we are young conscious minds in "school" or training for an advanced civilization. Maybe the aliens are fragmented memories of the real world... maybe alien abductions are actually doctor's visits of a sort for our real bodies where we are temporarily and/or partially unplugged from the simulation for some undisclosed reason. Maybe abductee minds are masked with false/confusing memories which lead them to believe they are having experiences with space aliens so as to not break the continuity of the simulation.
Man... I should either write Sci Fi or stop plagiarizing "The Matrix"... or then again, maybe the actual author of "The Matrix" (hint: NOT the Wachowski Brothers) knew something about the truth?...