One huge question: why are the Leviathan after Sam and Dean?

We know the Leviathan can't be killed... as of yet. The Leviathan know that no one knows how to kill them. So, why are they spending a huge amount of time and energy on hunting down two brothers that couldn't do anything anyway? For a group of evil creatures with a larger plan, it seems rather odd that they would even bother with Sam and Dean when they could be infiltrating and eating their way up the human ladder.

Of course, now, and by pure accident, Sam and Dean figured out how to slow the Leviathan down and cause serious damage. Who knew that borax would be the first key to defeating them? Guess Leviathan persistence backfired and gave the brothers a real chance at stopping them.

Although, I would say that it was fun watching the evil doppelganger versions of Sam and Dean. Their conversation in the diner was rather humorous as the two Leviathan discussed the Winchesters. Dean having a hero complex, a lack of relationships, and thinking he's hilarious, while Sam has full on mental problems illustrated the brothers in a spot on and clever way. I loved Evil Sam's line about having a brother with as many problems as Sam and flatly stating, "I ate him."

The best moment of the episode had to be Sam and Dean sitting in the car and Dean lip syncing Air Supply. It was simply easy to laugh as Sam awkwardly looked at Dean while Dean tried to mouth the words to "I'm All Out of Love." It's certainly up there in comparison to his "Eye of the Tiger" rendition.

Additionally, I loved the transition to Sam figuring out the direction the Leviathan were taking their murders. The flashback footage of their first hunts was a nostalgic look back that again tied into the present day issues.

Obviously, Jensen Ackles had a chance to shine with his comedic timing, but he was finally able to play something of an evil version. He hasn't had nearly as many opportunities to portray different characters on the show, but his sinister side was in full believable swing. The way his Leviathan self simply revealed that Dean killed Amy was a surprise. I'm so used to the hesitation and cut off of information that his directness was something of a shock. I'm sure Sam was more shocked, of course.

Finally, I love that Bobby's getting his opportunity to have his own love interest. Sheriff Mills brings out a softer side to him that makes them work well together. And wow that kiss! He definitely took things into his own hands, even if part of the reason may have been her unlikely assistance in discovering the borax.

So, up until the FBI agent revealed he was a Leviathan, I had rather enjoyed "Slash Fiction." There was plenty of humor, the brothers working together, cinematic shout outs from Pulp Fiction to Dirty Dancing, and discovering what hurts the Leviathan. Things were moving along at a fun and entertaining pace.

And then the ending took place.

The leader of the Leviathan was finally revealed and he still wants Sam and Dean dead. Why? Still no idea but he didn't seem overly menacing. And does anybody notice how bad guys love to dress in suits?

Crowley returned (yay!) and made an offer to team up with the Leviathan. The leader flat out refused and even threatened to end Crowley and his demon brethren. Surely, it was an attempt to establish the Leviathan prowess for the audience, and the possibility that Crowley teams up with Sam and Dean, but it just felt so boring. Nothing really happened there besides a muffin joke.

Then there was the most obvious lackluster moment with Sam and Dean's breakup. Sure, it was inevitable but it felt so bland and done before. I understand Sam's anger and frustration, but leave? To where? C'mon, Sam, taking this route never goes anywhere good. I just hope their seperation doesn't last long because I want the brothers to be back together with their playfulness and teamwork. That's the Supernatural I love.

Maybe a little Air Supply will bring them back together. Cue the music: I'm all out love, I'm so lost without you...

Sean McKenna was a TV Fanatic Staff Writer. He retired in May of 2017. Follow him on Twitter.