Shelob is the giant spider that attacked Frodo and Sam in Cirith Ungol in J.R.R. Tolkien’s The Lord of the Rings.
Shelob appears in The Two Towers, the second volume of Tolkien’s novel. She lives in a tunnel near the pass of Cirith Ungol, above the route toward Mordor. Gollum guides Frodo and Sam into the area, intending that Shelob will kill them so he can recover the One Ring.
Shelob poisons and stings Frodo, but Samwise Gamgee drives her away with Sting and the light of Galadriel’s gift. Sam then takes the Ring temporarily, believing Frodo to be dead, before discovering that Frodo is paralyzed rather than killed.
Shelob is described as a descendant of Ungoliant, an even older monstrous spider from Tolkien’s mythology. Ungoliant is therefore a related but different character, while Lobelia is a hobbit of the Shire and not a creature of Mordor.