Season 5, Episode 4
After getting a phone call from Sam informing him that Sam is the vessel of Lucifer, Dean wakes in a post-Apocalyptic future where he's been sent by Zachariah to show him what will happen if he continues to refuse Michael. The Croatoan virus has turned most of the population into mindless zombies, and Dean's future self is the leader of a refugee camp, caring about nothing but killing the Devil in revenge for Sam. Future-Dean takes his past self on a suicide run against Lucifer, armed with the Colt, and ends up dead. Upon returning to his present, Dean still refuses to be a vessel and instead calls Sam to rejoin him in hunting.
For this episode = 12 humans.
For the series so far = At least 318 humans (of which 5 were witches), at least 82 demons, 28 ghosts, 11 vampires, 6 changelings, 3 gods, 3 shapeshifters, 3 zombies, 4 angels, 2 ghouls, 2 werewolves, 1 cat, 1 crocotta, 1 djinn, 1 dog, 1 rakshasa, 1 rawhead, 1 reaper, 1 rougarou, 1 shtriga, 1 siren, and 1 wendigo.
- Achilles' Heel: Discussed when Dean tells Sam that they are each other's weakness, and they are stronger when they're apart as they are always being used against each other.
- Acting for Two/Talking to Himself
- Bad Future: Oh dear Heaven is it. Dean gets a sneak peek of five years into the future where he meets a jaded Jerkass version of himself, a strung-out and oversexed Castiel, and Lucifer wearing his brother like a cheap suit. The Croatoan virus has ravaged the planet, the angels have thrown up their hands and left, and Sarah Palin is president.
- Broken Aesop: An In-Universe version. The lesson Dean takes away is not that he should let Michael possess him, but that Sam keeps him human and he needs to hook up with his brother.
- Broken Angel: Castiel states in so many words that he's "not an angel anymore". He's also a junkie, an alcoholic, and running a cult of the enlightenment-through-sex variety.
- Call Back: the Croatoan virus returns.
- Crapsack World: Not exactly a surprise. Although given the show's usual Angst level, it's more like "Crapsack Turned Up to Eleven World".
- Dramatic Thunder: A clap of thunder punctuates pretty much every word Lucifer says.
- Future Badass: Sorta, although present-Dean is a badass already. Maybe it's more like "future even-more-badass-through-being-a-heartless-Jerk Ass".
- Future Loser
- Future Me Scares Me
Dean: Oh, so we're torturing again? No, that's good. Classy.
- Inverted with Cas who says he quite likes Past Dean, cause he's still got his sense of humor.
- Get It Over With: Dean arrives just in time to see Lucifer-in-Sam's body casually snap future!Dean's neck. Realising all is lost, Dean tells Lucifer to go ahead and kill him. Lucifer quips, "Don't you think that would be a little...redundant?"
- The Hedonist: "It's the end, baby! Might as well bang some gongs before the lights go out."
- Ho Yay: When Dean tells Sam why they can't be together, it sounds a lot like a breakup.
- Humans Are Bastards: Lucifer gives a Motive Rant over how Earth is God's last and greatest creation — and then he made humans to fill it. Lucifer was cast out of Heaven when God told him to love humans more than Him.
"Look at what six billion of you have done to this thing. And how many of you blame me for it."
- Inconvenient Summons: Inverted
- Jacob Marley Warning
- Knockout Punch / Smash to Black
- Man in White: Lucifer-in-Sam is dressed in a smart, white suit. It adds to the Uncanny Valley.
- Neck Snap: Lucifer steps on future!Dean's neck and casually breaks it.
- Only Electric Sheep Are Cheap: Invest in toilet paper. It's worth more than gold.
- Revenge Before Reason: Future-Dean is willing to use all of his friends, including Cas, as bait just to make sure he get a shot at the Devil.
- Senseless Sacrifice: Future!Cas and his allies sacrifice themselves to get Future!Dean to Lucifer only to have Dean fail. Made worse when you realize later that the Colt can't kill Lucifer so the mission was doomed from the start.
- Something about a Rose: Lucifer's confrontation with Dean takes place in a rose garden.
- Soundtrack Dissonance: Drunken soldiers gun down infectees to "Do You Love Me?"
- Shoot the Dog: Future!Dean is all about this.
- Spot the Imposter: Dean tells Future-Dean about a really confidential moment involving wearing ladies underwear.
- Take That: Against Sarah Palin.
- Total Party Kill
- Uncanny Valley: Lucifer-in-Sam doesn't quite seem to know how to work his face, which is some pretty good acting on Jared Padalecki's part.
- The Virus
- We Want Our Jerk Back: Dean to Stick-up-his-ass-Castiel after he teleports Dean out just in time.
- Wham Line
"Sam didn't die, he said yes."
- What the Hell, Hero?
- You Can't Fight Fate: Lucifer gives Dean a lecture about "whatever you do, no matter what details you change, we will always end up here". Dean responds with "Screw Destiny", but it's unclear till much later how that works out.
- Zombie Apocalypse: The Croatoan virus turns people into fast zombies of the "infected with rage" variety.
- Zombie Infectee: Future Dean does a sudden Boom, Headshot on a member of his team he claims has been infected.