When angels are described in the Bible, it's often in strange and abstract terms, beings with multiple faces, legs made of burning bronze, eyes where eyes shouldn't be, etc. As if the writer was having difficulty comprehending what they were seeing,much less finding language for it. And the first thing angels do when they encounter humans is tell them not to be afraid, because of course the logical and proper reaction to skyscraper-sized interlocking, burning, eye-covered wheels with multi-faced, multi-winged beings in the middle is bowel evacuating terror.

And of course, many of Lovecraft's eldritch horrors were simply aliens that were so alien that the mere sight of them broke human minds, and that were no more concerned for humanity than humanity is for a particular anthill.

That's probably what an actual encounter with an alien is going to be like for us. We'll try to understand why a living infinite-dimensional hypersphere made of flesh made of time whose eyes are our eyes all at once just showed up and "unfolded" our sun into a non-Euclidean shape we can't even describe mathematically without being driven slowly to madness, while it won't even know we were there.