>>212725077 (OP)When the representation is too uncanny, they come off as non-literal representations of human psychology rather than genuine attempts to depict possible life-forms.
I don't know about the films, but in the Solaris book there's a bunch of detail about the planet's "ocean" being one giant living thing, which induces the hallucinations.
Another one that hasn't been filmed yet is Sun Diver, which features beings made of plasma living in the outer layers of the sun.