Shelob is the giant spider defeated by Samwise Gamgee in J.R.R. Tolkien’s The Lord of the Rings. Sam fights her in the Pass of Cirith Ungol while protecting Frodo and the One Ring.
Shelob lives in a lair near the border of Mordor. She attacks Frodo, stings him, and leaves him apparently dead, but Sam uses the sword Sting and the phial of Galadriel to drive her away. He then takes the Ring temporarily, believing Frodo has died, before discovering that Frodo is still alive.
Shelob is descended from Ungoliant, a much older primordial spider-like being from Tolkien’s mythology. The two characters are therefore related, but they are not the same creature. Shelob’s name is an English compound meaning “she-spider.”