I'm sure I'm probably way behind and this has been discussed already....

[irishka1205]

But from the moment I learned of the title of 4.18 episode, Monster at the End of the Book, I got a sneaking suspicion that it was Sam.  That was before I read trystan830 's post and realized that it's actually a Sesame Street book, which I actually own as well.  I'm blaming my slow-ness on a stressful week, lol.  So, especially since we all obviously know how THAT book ends, I am pretty much convinced it's Sam.  I did also just read the article saying the same thing on BuddyTV web site.  http://www.buddytv.com/articles/supernatural/supernatural-who-is-the-monste-27549.aspx .  Except, maybe it's denial, maybe it's something else, but I don't think Sam is Lucifer.  Maybe I just don't want it to happen and don't think it would work.  The biggest reason why I'm enjoying Sam's storyline, especially this season (as little as we got of it), is because his descent into darkness is a result of choices he makes.  There's reasoning behidn it. Yes, it's scary and it breaks my heart and I imagine this will not end well for Sammy.  Because especially now that he saw that he's still not strong enough to take on Lilith, he'll try even harder, drink more demon blood, try something else to get to the point where he can kill her.  But like I said, he's making a choice here.  As Jared said at the LA Con, he's choosing to sacrifice himself in order to stop Lilith, save the world, and save Dean.  If Lucifer is caged in Sam's body or Ruby trying to turn Sam is so that he becomes a vessel for Lucifer, that takes that choice out of Sam's hands.  And I don't want that.   I do still feel that the monster at the end of the book is Sam.  Because he will cross that line. I have no doubt about that.  I do wonder whether we'll find that out at the end of this season or not.  It seems to be going that way, but... Kripke will have to somehow then bring the boys together.  Because the show will not work otherwise.

Just a warning, I'm totally spoiler free, so please, don't tell me how this season ends.  Please.