Check out this awesome never-before-seen photo of Elijah Wood as a Gollum like creature. As you all know Frodo could have very well had the same fate as Gollum in The Lord of the Rings if he didn't keep pressing forward on to Mount Doom. We saw little glimpses of Frodo with that Gollum look throughout the journey because he was struggling with the addictive power of the ring.
Apparently Peter Jackson had a scene in mind where we would actually see Frodo had the ring completely taken over him. This photo features a makeup test for the scene that was never shot, and he looks freakin' frightening. I would be interested to know how Jackson would have incorporated this into the story.