Sickness Theory

The smoke monster is the subject of much controversial debate. From the hieroglyphics on Ben's secret door to those on the temple ruins we saw last Wednesday, we can assume that Smokey resides near or in the Temple we've heard of but never seen. Some people also think that the black ring of ash around Jacob's cabin (seen in season three's The Man Behind the Curtain) is actually some form of Smokey.

Here's my theory:

Smokey is a collection of all of the souls of the people who've died on the island. When the armless french man yelled "Aidez-moi" or "Help me!" it wasn't actually him, but Smokey, masquerading as him. Those that went in after him came out with different souls. Smokey took their souls and replaced them with some it already had, souls set on protecting the island. That's the sickness. Of course, it doesn't happen to everyone, only to those the island views as a risk or doesn't want to outright kill much the same as Eko. Speaking of Eko, the french people could also be similiar to Yemi, but Yemi was an apparition, not a physical being. So Yemi (eko's brother, seen in season three) shows that the smoke monster can manifest itself and speak. Can the smoke monster, for lack of a better term, possess people as well? We'll see.