“But still she was there, who was there before Sauron, and before the first stone of Barad-dûr; and she served none but herself, drinking the blood of Elves and Men, bloated and grown fat with endless brooding on her feasts, weaving webs of shadow; for all living things were her food, and her vomit darkness.“
Shelob was a Great Spider. She was the greatest offspring of Ungoliant. During the Third Age she lived in Mordor and was known to feed indiscriminately, preying on orcs, men, elves, and dwarvesalike. She was encountered by Frodo Baggins and Samwise Gamgee in their quest to destroy the One Ring.
Shelob’s early history is completely unknown, save for the assumption that she was born in the Ered Gorgoroth during the early First Age. By the Second Age, she often feasted on her own children, and that at some point after fleeing from Beleriand, yet long before Sauron took the land of Mordor for himself–even before the first stone of Barad-dûr was placed–she spun a dark lair in Ephel Duath(Mountains of Shadow), near Cirith Ungol in the passes above Minas Morgul. For hundreds of years, she resided in this mountainous region, making a labyrinth of webs within a network of caves to better trap her prey, which included all creatures great and small. She feasted primarily on those who wandered into her web, although if a particularly juicy morsel was available, she would silently pursue and kill it.
Sauron was aware of Shelob’s presence in the mountains and allowed her to dwell there. It proved to be beneficial to them both: in return for protecting the most secret passes into Sauron’s domain, Shelob got free reign to do as she would. Sauron was known to be somewhat fond of her, and in a rare show of humor, was even known to refer to her as his cat, as she didn’t necessarily accept his authority, but still lived on his lands. Like a pet cat, Sauron would sometimes give her food in the form of prisoners that he had no more use for, or servants who had displeased him.