Shelob comes from the Tolkien Universe. She is a huge spider who attacks Frodo and Sam at Cirith Ungol as they enter Mordor.
...Great horns she had, and behind her short stalk-like neck
was her huge swollen body, a vast bloated bag, swaying and
sagging between her legs; its great bulk was black, blotched
with livid marks, but the belley underneath was pale and
luminous and gave forth a stench. Her legs were bent, with
great knobbed joints high above her back, and hairs that stuck
out like steel spines, and at each leg's end there was a claw.
[ The Two Towers, by J.R.R. Tolkien ]