Upon reading the last couple chapters of the Two Towers again, I’ve thought of something interesting. Is it possible that Shelob can, and does, cast an Unlight in her lair, even as Ungoliant did? Listen to this description of the atmosphere inside her cave:
I added emphasis to the words “black vapour” because that is a crucial quality of the Unlight that Ungoliant cast so long ago:
“Drawing a deep breath they passed inside. In a few steps they were in utter and impenetrable dark. Not since the lightless passages of Moria had Frodo or Sam known such darkness, and if possible here it was deeper and denser. There, there were airs moving, and echoes, and a sense of space. Here the air was still, stagnant, heavy, and sound fell dead. They walked as it were in a black vapour
wrought of veritable darkness itself that, as it was breathed, brought blindness not only to the eyes but to the mind, so that even the memory of colours and of forms and of any light faded out of thought. Night always had been, and always would be, and night was all.”
“Ungoliant belched forth black vapours as she drank…”
Now it seems like the darkness in Shelob's lair is of similar quality as the Darkness that was cast by Ungoliant, yet I think it's fair to say that its effect was not as powerful as Ungoliant's. Do you agree with all I've said?
“the Darkness that followed was more than loss of light. In that hour was made a Darkness that seemed not lack but a thing with being of its own: for it was indeed made by malice out of Light, and it had power to pierce the eye, and to enter heart and mind, and strangle the very will.”
The hands of the king are the hands of a healer, and so shall the rightful king be known.