If you're not caught up on the finale of "Orphan Black," may we suggest you back away from this post now (and not slowly), as it contains perhaps the biggest game-changing spoiler in Clone Club history.

OK, so. Let's talk about Mark, shall we? Because Mark is not really unique. Mark is, shall we say, one of a few with no family, too? That's right, folks: there's an army of male clones out there in the world and they all share a face with Ari Millen, the actor who — up until this point — was known solely as Prolethean convert Mark. He's been creeping us out all season and now we know why...

Mark is a clone. (And here all this time you thought the game-changer was the trans clone.)

Which means we haven't seen the last of him, or even all of him, yet. Not by a long shot. Ho-ly sestrahood, folks!

Now, the reveal that Project Leda was merely one part of the cloning operation was not all that surprising — people have wondered since season one if there were male counterparts and who that might be (many fans hoped it would be revealed to be Felix). But the fact that we found out, at the end of the season, that we'd been dealing with a male clone the whole time? W-O-W. That's a reveal, folks. Project Castor is a-go.

Mark's existence as a clone opens up the floodgates in a really big way: the loyal Prolethean now married to runaway Gracie (who is pregnant with one of Helena's babies) will have to contend with at least two other iterations: an armybrat loyalist and a seemingly Helena-esque psycho, currently trapped at Marian Bowles' house. And the mystery of how the human cloning experiment began has gotten a heck of a lot deeper, and likely more political. If there are male clones in the club, how much deeper does this mystery go?

The possibilities are now truly endless.

Personally, we're a bit obsessed with this twist: what'd you think of the revelation that Mark is a clone? Let's discuss in the comments.