Ok, hear me out.
We always depicted aliens with a 'physical' form or in a way that we are able to visually see them with our eyes...
But what if we leave that sort of restrictive trope of eldritch space sci fi horror and use any other form within our understanding?
For example... Sound. Strangely enough, I got the idea when I was playing Wuthering Waves lol.
I like the idea of characters using 'Resonance' or sound to summon abilities and creatures like the Tacet Discords...
What if these 'sounds' had no physical form at all but instead stay in Resonance form? Alien Sounds!