Supernatural Season 10 Spoilers: Where Does Dean's Storyline Go?

Supernatural stars Jared Padalecki and Misha Collins had teased major developments at the end of the Season 9 finale. Padalecki said Supernatural fans are in for a long summer break because episode ends with a "huge" cliffhanger that changes the show's landscape "big time." Collins took it a step further. "More than any other season before, this season finale has implications for Season 10." He described the ending as "chilling." "It may be the best last 10 seconds of a season that we've had in five years."

And the ending definitely lived up to the hype.

[WARNING: MAJOR SUPERNATURAL SEASON 9 FINALE SPOILERS BELOW]

In the final moments of the episode, Crowley brought the First Blade to Dean's lifeless body and placed it on his chest. He told him to let the feelings take control and commanded Dean to open his eyes. And in the final shot, Dean opened a pair of black, demonic eyes.

Dean Winchester has become the thing he fears and hates most: he has become a demon. The final moments of the Season 9 finale truly altered the DNA of the show, as one of the brothers is now, seemingly, under the influence of Crowley. It was a bold maneuver that truly freshened up a show that had started to grow a bit stale but that had received an adrenaline shot in recent seasons.

This also opens up numerous possibilities for the show, so let's explore some of the options for where Season 10 can take Dean's storyline:

1) Sam could cure him.

Much of Season 8 dealt with Sam and the three trials, and the final trial was "to cure a demon." Sam learned how to do it and nearly succeeded with Crowley, so it stands to reason that he could do the same with Dean. Of course, it nearly killed Sam when he did it last time, but if there's one thing the Winchesters do, it's sacrifice themselves for each other.

It's also unclear if the trials would be complete if Sam did cure Dean. Would he drop dead? Would the gates of Hell close? It seems a bit too easy and convenient, as the show could wrap this up in about three episodes if it went this route.

2) Dean could be a sleeper agent.

As Meg once said on this show, "Crowley's always the problem." Even though the King of Hell has been buddying up to the Winchesters in Season 9, he still could easily serve as the overarching Big Bad for Season 10 (whether it's the final season or not).

So really, there's no reason for Crowley to tell Sam what happened. He can send Dean in as a sleeper agent and work him like a puppet from inside Team Free Will. It would be a chess move worthy of Crowley and would set up some interesting conflicts for Season 10.

3) Dean could be a total BAMF.

It's possible Dean could just go completely off the rails and turn full-on demon next season. This would force Sam and Castiel to make a decision about what to do with him. Do they have it in them to hunt down their friend and brother?

4) Dean could retain part of his humanity.

Dean may be a demon, but we've seen demons on this show (including Crowley) retain semblances of their humanity. If a part of Dean is still human or still connected to Sam in some way, then we could have an interesting hybrid version of Dean on our hands.

What do you think, Supernatural fans? Where will the show take Dean's storyline in Season 10? Let us know your thoughts, guesses and opinions in the comments below.