That alien "greys" as we know them aren't extra-terrestrial at all but sub-aquatic - there features derived partially from evolving from a sea-based creature such as a Dolphin explaining there skin type, there short stature and large eyes due to evolving in sub-aquatic caves where there's limited light causing them to evolve large dark eyes and the small caves would mean evolution would favour the short not the tall as it does on the surface - also gravity is slightly stronger down there.
There small mouths are due to eating fungus and moss or plankton and although perceived to communicate telepathically by us they're actually using high pitch clicks (similar to Dolphinese) but out of our hearing range (why dogs always bark when they're around).
Flying saucers are such a shape due to their submarine requirements as they need to travel through the sea not just the air.
Due to the far more hazardous environment they evolved in they're a peaceful people but they haven't contacted us directly due to fear of attack and haven't "invaded" the surface as it holds no merit for them, the sun too bright for the eyes and millennia underground means they get sun-burn/cancer real quick.
Thing I like most about this one is I made it up a few years back
There small mouths are due to eating fungus and moss or plankton and although perceived to communicate telepathically by us they're actually using high pitch clicks (similar to Dolphinese) but out of our hearing range (why dogs always bark when they're around).
Flying saucers are such a shape due to their submarine requirements as they need to travel through the sea not just the air.
Due to the far more hazardous environment they evolved in they're a peaceful people but they haven't contacted us directly due to fear of attack and haven't "invaded" the surface as it holds no merit for them, the sun too bright for the eyes and millennia underground means they get sun-burn/cancer real quick.
Thing I like most about this one is I made it up a few years back