The Shelob was a large arachnid that stalked the tunnels near Mordor.
When Frodo and Gollum are walking through the tunnels, Gollum betrays Frodo and leaves him trapped in Shelob's webs. Frodo manages to get through the caves but is followed by Shelob who stings him rendering unconscious, and then wraps him in web. Sam comes and finds Frodo distraught thinking he is dead starts to cry over Frodo, but hears a group of orks approaching so he hides behind some rocks. One of the orks says that he is not dead, relifed he goes back down to the spot were Frodo is after the orks leave and proceeds to remove the webbing. unfortunately Shelob return for its prey and attacks Sam, but Sam uses his sword to cut into Shelob's head. Still attacking, Sam used his sword and plunged it into Shelob's abdomen causing it to scream in pain, and runs off back into her cave.