What was Shelob, and more importantly, what was Ungoliant?

[Nerwen]

Originally Posted by Legate of Amon Lanc

Can I pop in and say that it would make very good sense on this matter if she were an Ainu? Like the Balrogs, who were originally flame spirits similar to Arien, but were persuaded by Morgoth to join him...

This is a good parallel for another reason. Earlier, Balrogs were meant to be creations of Morgoth; Tolkien changed their origin to fit in with his later ideas. Same with Ungoliant.