It's that time again. Soon you'll be packing off to your parents' place, for turkey and inquisition. But what's the worst that could happen? Your parents could be aliens, robots, pod-people or evil doppelgangers, according to science fiction and fantasy.
Top image: strip by Rozsdás, based on an idea from Robot Chicken, via Darths and Droids.
Your parents could be evil duplicates
And before you ask, "How would I be able to tell the difference?", consider how dreadful it could be:
In Philip K. Dick's "The Father-Thing," a young boy realizes that his father isn't really his dad any more. He's been replaced by some kind of alien duplicate, and this is one of the most sinister, chilling things that Dick ever wrote. The fake dad looks and sounds like the real thing, until he doesn't: "Ted Walton's face lost all familiarity. Something alien and cold gleamed out, a twisting, wriggling mass. The eyes blurred and receded, as an archaic sheen filmed over them. The ordinary look of a tired, middle-aged husband was gone." Only the other neighborhood kids will believe the truth.
Pretty much every version of the Invasion of the Body Snatchers story either starts with someone realizing that a parent isn't really their parent any more — or is about that, to some extent. Often, there's a scene where the kid or young adult tries to convince a therapist that Mom isn't really Mom, Mom is Wrong, but the therapist won't listen because that's what therapists do — scoff when you reveal the truth about stuff.
Or your parents could be alternate, idealized versions, like in the book and movie Coraline — nice and friendly, until they turn out to have some unpleasant plans for you.
Your parents could be aliens
In My Stepmother Is An Alien, Dan Aykroyd is a scientist who marries a woman (Kim Basinger) who turns out to be an alien who's been sent to Earth to investigate his experiments — and possibly destroy the entire planet. The only one who suspects the truth is the scientist's daughter (Alyson Hannigan), who gets stuck on the ceiling by the weird penis monster in Basinger's purse.
This is subverted somewhat in the Monsters episode "Parents from Space," where young Cindy's quasi-abusive stepfather Ward and mother June are replaced by rat-creatures from outer space — the aliens swap bodies with Cindy's parents. But when Cindy realizes the truth, she actually prefers her alien parents to the "real" things, so she winds up convincing the aliens to stick around, instead of swapping back as they'd originally planned.
It's also subverted somewhat in the sitcom My Parents Are Aliens, where the secret alien visitors are benign but clueless.
Your real father or mother could be your arch enemy
Just ask Luke Skywalker how much worse this type of family reunion could be. Instead of having some harsh looks while your folks pass the stuffing, and some uncomfortable questions about your love life, you could be getting your hand lopped off and having your dad try to convert you to the dark side.
"Spy-fi" shows are full of parents who turn out to be secretly evil or at least morally neutral. Poor Sydney Bristow probably wound up feeling glad she only had two parents, plus one surrogate dad figure — the Bristow clan were all spies, and mostly either evil or nasty. We still haven't quite gotten to the bottom of whether Chuck Bartowski's mom is evil or just mean. And then there's Wesley in Wanted, who finds out his father was actually a super-assassin (but wasn't an entirely bad guy, it transpires.)
In His Dark Materials, Lyra discovers her real mom is Mrs. Coulter, who's a major antagonist in the first book.
The kids in Brian K. Vaughn's Runaways all decide to spy on a gathering of their parents —- only to learn that their parents are part of a supervillain group called the Pride. They decide to go on the run and try to put a stop to their parents' evil doings — which turns out to be harder than superhero comics would lead you to believe.
Poor Scarlet Witch and Quicksilver discover that their real dad is the mutant villain/rabblerouser Magneto, who they thought was just their former evil boss from the Brotherhood of Evil Mutants, was actually their dad. And as you'd expect, this changes almost everything they thought they knew about them and sets the stage for the eventual "Disassembled" and "House of M" storylines where Wanda goes sproing. Photo by Aaron Capone.
In Fables, Pinocchio discovers that his "father," Gepetto, isn't dead — and Gepetto isn't just a victim of the Adversary, but is actually the Adversary himself. Worst of all, Pinocchio has a geas placed on him that keeps him from acting against his "father"'s interests.
Invincible thinks that is father, Omni-Man, is a superhero from an alien race that preserves peace in the universe. And then he discovers the awful truth — Dad is actually an alien infiltrator sent to prepare Earth for alien invasion.
Spider-Man 2099 himself, Miguel O'Hara, finds out his dad is actually corporate scumbag Tyler Stone, who got Miguel hooked on a genetically modified drug and indirectly turned Miguel into Spider-Man, is actually his evil, eeeeevil dad.
There are tons more examples of parents who turn out to be evil over at TVTropes, including Soranik Natu finding out Sinestro is her dad, and so on.
Your parents could be monsters or demons
In Reaper, Sam finds out that his parents sold him to the Devil before he was even born. But later, he discovers it's even worse — his father is the Devil. Luckily, it's the charming Ray Wise.
What's the worst case scenario if your dad is the Devil? Probably that he's Al Pacino's Devil in 1997's The Devil's Advocate — Pacino's Devil wants his son (Keanu Reeves!) to have sex with his own half-sister, so the Devil can have an in-bred grandchild — the Antichrist. Also, Pacino gets his son Keanu to go work at his Satanic law firm, defending Satanic cultists, pedophiles and other upstanding members of society.
In the Masters of Horror episode, "The Fair-Haired Child," Johnny drowns on his fifteenth birthday — but his parents won't leave well enough alone. They keep sacrificing innocent children to a demon to bring Johnny back to life, which has the effect of turning Johnny into the demonic "Fair-Haired Child." But Johnny falls for the last girl who's going to be sacrificed for his resurrection, and they team up to destroy his parents instead.
Or hey... your dad could be Freddy Krueger himself. It happens to Maggie in the sixth Nightmare on Elm Street movie, Freddie's Dead: The Final Nightmare.
Or you could be like poor Azrael — Batman's first alternate — who was raised by evil cultists and brainwashed to become an evil assassin. Worst yet, it turns out that Azrael's real "dad" was a monkey, as he was grown in a test tube from various animal and human DNA, to give him his special abilities.
Your mom could be bitten by a Sumatran Rat Monkey, like poor Timothy in Peter Jackson's Dead Alive, and she could turn into a kind of pseudo-zombie who literally falls apart during a fancy dinner party. Classy!
Society, directed by the great Brian Yuzna, is the classic example of this trope — Bill's wealthy parents and sister turn out to have adopted him — and they, along with all of the other rich people in Beverly Hills, are actually a different species. They feed on poor people via "shunting," stealing their life force — and the film ends with a hideous scene where Bill's family merges into a hideous undifferentiated blob of incestuous, parasitical crap — this is the absolute worst-case scenario of what could happen on your visit home. In fact, you should probably track down a copy of this film to watch beforehand.
Additional reporting by Chelsea Lo Pinto and Katharine Trendacosta.