>>718035573
In terms of book lore, I actually have no problems with a humanoid Shelob, if you go with the theory that Ungoliant was a Maia.
Lúthien for instance inherited powers from her mother, such as stealing the shape of a vampire, and her granddaughter Elwing had the potential (with the initial aid of a Vala) to shapeshift into a bird. So it wouldn't be crazy to think that Shelob, a daughter of a Maia, could morph into a sexy goth bitch.