Sam's evilness is becoming manifest, leading me to suspect that I was wrong - Lucifer is no longer present in his body. For Sam is now worse than he and Ilbis and Satan together.
So who is it? What command's Sam's thoughts now? For what master is the middle Winchester now obeying?
here is my guess....and you get a cookie if you recognize the references:
He who Sleeps behind the locked door in the midst of the ancient city within Antarctica, One who drives men madder than Griffin the invisible, the cythonic god who will only awaken when the stars are in their places and He shall push aside the sandtrout as Sam shouts for Him to one and all and sundry that "THE SLEEPER HAS AWOKEN!"