In some works, a mother or a father is simply missing and it'll get chalked up as Disappeared Dad or Missing Mom, no problem. The character might not care that their parent is gone and is happy without them. Or, finding out who their parents are might just be the character's whole reason for being. One day, said dad or mom might just show up, and reveal themselves to be something unpleasant. Whether it be a bad guy, a criminal, thief, or even a combination of the three, their reveal is usually the exact opposite of how they imagined their parent to be. All their dreams of a happy family upon reuniting with their Disappeared Dad or Missing Mom are brutally dashed. It's the aversion of the fairy tale ending where all is made right when the character is reunited with their parents.
This trope also covers a character just finding out that their parent died horribly, was found living in some place undesirable, or simply, anything unpleasant.
If the dad or mom is dead and the character finds out posthumously he/she was a bad guy, then they can come up with all kinds of theories to justify their parent's actions in absentia. Only if they're alive can those be shot down.
- In Code Geass it's revealed that Lelouch's and Nunnally's sweet, deceased mother wasn't nearly as nice as presumed. Marianne was alive the whole time, is a Big Bad alongside her husband, and it's left vague if she even loved her children.
- In Kill la Kill, the first time protagonist Ryuko met her mother Ragyo involved said mother ripping her heart out of her chest. That's not even factoring in the fact that Ragyo sexually abused her other daughter for the past 12 years and plans on turning the human race into food for an alien parasite.
- Rinne's father Sabato Rokudo, who is a complete Jerk Ass who owns an illegal business stealing the souls of still-living people for profit. He steals left and right and is constantly scamming people. He frequently steals his teenage son's own hard earned money, forcing him to live in poverty and leaves him with debts by purchasing things in his son's name, basically committing identity theft. He's the primary antagonist in the series and even though it's Played for Laughs it's pretty messed up.
- In an obscure Aladdin comic book, he finds his long-lost uncle who later turns out to be a thief using him as a distraction. Before he left he said to Aladdin that he knows the truth about his parents. It is unknown of how much the creators of this comic were in touch with the movie creators, or if they were both following a precise lore bible, but it actually ties in pretty well with Aladdin and the King of Thieves.
- In Runaways, Molly spent years deluding herself that her parents, despite being supervillains, could not possibly have been as bad as the rest of the Pride. In "Mollifest Destiny", she meets one of her parents' former enemies, who tells her that they tortured him for seven years straight just for mildly inconveniencing them. She punches him straight through a roof, and then breaks down and cries, unable to reconcile what she's been told about her parents with her own memories of them.
- In Batman Jason and Bruce spend a considerable amount of time looking for Jason's biological mother after he realizes that he's not related by blood to Catherine. Jason, excited about the prospect of having living family, tells his birth mom Sheila Haywood about his secret ID as Robin and she immediately betrays him to Joker, who then proceeds to beat Jason almost to death and blow him up. Upon his resurrection Jay is not upset to learn Sheila died in the blast as well, although his last action in life was trying to save hers.
- In the Bleach fanfiction Moving Forward Orihime's long-absent father shows up on her doorstep but he isn't there for a heart to heart talk. He is there to take her home so he can get her mother's life insurance. And he is ready to use force to make her come with him.
- In Cellar Secrets, we have a variant in that Satsuki and Nui find out that, not too long after he left the family, Souchiro died as opposed to having found out that he had done something horrible. However, while they knew he died, they don't find out how he died, until chapter 21, where we find out that he died in a car accident, leaving Satsuki to be relieved that he died rather quickly (his neck was broken) and not because what she would have thought previously.
- Fire Emblem Fates: Aftermath: Once Corrin is told that Anankos was his father, he's naturally shocked that he's the son of the insane dragon god that tried to destroy humanity. Even after it's explained that it was Anankos' good half that married Mikoto and sired him, Corrin cannot visualize his father as anything but evil.
- In Joe Dirt, after Brandy calls Joe claiming his parents to be dead, his parents manage to find him, but he then finds out that they left him behind at the Grand Canyon on purpose and only found him to ride on the coattails on his newfound popularity. Brandy then tells him that she did indeed track them down for him and decided not to tell him after finding out how horrible they were.
- In The Empire Strikes Back, Luke learns that Vader is his father, and he's clearly devastated to learn that his dad's an evil killing machine who strikes terror into the heart of nearly the entire galaxy. His only hope is to turn his father good again.
- In Maleficent, Aurora finds out that her father, who she didn't even know was alive, was the one who disfigured her beloved "fairy godmother" Maleficent.
- In the Geekomancy series, it's a Missing Mom who's the unpleasant reveal. Ree Reyes finds out that her Long-Lost Relative was thought dead... But Ree's mom was alive and had gone back to Geekomancy. In the years since leaving her daughter, Branwen had been killed, brought back from the dead, and enslaved by a demon Duke into a murderous Hexomantic witch. Ree slides up and down the emotional spectrum between crushed and furious about this. She also has a healthy side order of guilt because she is keeping the truth of her mother's whereabouts from her father. Ree is certain he'd be devastated to know she left him because she couldn't reconcile her geekomantic talents with being a wife and mother and because she'd shacked up with an old lover in the process.
- In Harry Potter and the Order of the Phoenix, Harry looks into Severus Snape's memories for a while and finds out that his deceased father, whom everyone who knew him called a great man, was, in fact, The Bully during his school days who regularly abused Snape. Subverted as James's friends later assure Harry that James had his issues, but he became a better person beyond the context of that one memory Harry saw from Snape's perspective, and part of the reason for James being so harsh towards Snape was because Snape would often do the same to him.
- In Outcast of Redwall, Veil is the son of the warlord Swartt Sixclaw, though neither attempts to do anything about it. It's only the older members of his horde that see the resemblance (and of course, the fact that both have an extra claw on their hand).
- In The Wizard Heir, Seph finds out that, while his parents are not evil as such, his mother gave him to a foster mother instead of raising him herself, in order to keep him safe, and that she never told his father that he has a son. Less than stellar, one might say.
- A variant in Animorphs: just before the two-year anniversary of his mother's "death," Marco discovers that his mother is actually the host body of Visser One, who faked the death when she was reassigned off-planet. Marco had actually been planning to quit the team but stayed on with the goal of eventually freeing his mom from the Yeerks. He succeeds forty books later.
- Subverted in the Inheritance Cycle. In the second book, Eragon is told by Murtagh that he is the son of Morzan, the last of the Forsworn and overall bad person. As it turns out, however, while his mother was Morzan's wife, his father is actually Brom.
- Bones: In Brennan's Back Story, her parents disappeared when she was 14 years old. As an adult, she learns that her parents were criminals who abandoned Brennan and her brother in order to keep them from being murdered by other criminals. She finds this out after discovering her own mother's remains in the Jeffersonian's vault of unknown persons' remains. Her father Max is still alive and is a recurring character until he sacrifices himself to save his grandchildren from an attack by an old enemy of Booth's.
- In Cheers episode "The Bar Stoolie", Cliff's Disappeared Dad shows up after being missing for years. They have a great time bonding until Cliff's dad confesses that he's on the run for real estate fraud. Cliff refuses to follow his father to Australia.
- Doctor Who: Downplayed in "Father's Day." Rose gets the Doctor to take her back in time to the day her father died, and when she meets him she discovers that he isn't the wonderful man "always having adventures" that her mother described, he's a gadabout looking for his next get-rich-quick scheme. However, he does make a Heroic Sacrifice when he learns that he was supposed to have died but Rose saved him from being hit by a car and changed the world for the worse.
- In the series Murdoch Mysteries, the title character first mentions his father Henry during an interview for a promotion, but only to say the man worked as a fisherman and that they've lost touch. In a later episode, Murdoch and Constable Crabtree discover the man unconscious at a murder scene, and viewers learn that Henry has been an alcoholic for years and that William thinks his father is responsible for his mother's premature death. In a subsequent encounter, William investigates a shady land deal that's tangled with mining and murder only to have his father's name come up, and learns he has a half-brother that Henry fathered with a woman to whom he was not officially married.
- In Night Court: Harry Stone thinks that Harry Stone Sr. was his father. When it turns out that his stepfather Buddy (who met Harry's mother when they were both in a mental institution) is his biological father, it freaks him out.
- Orange Is the New Black: While Alex was growing up, her mother always told her that though they were poor, she should feel proud that she was the daughter of a great man - a rock star. However, when Alex finally gets to meet him as an adult, she finds a washed-up obnoxious jerk whose first reaction to finding out that she's his daughter is to laugh that it's good he found that out before he hit on her.
- In Peaky Blinders, Arthur Shelby discovers that his Missing Dad Artur Sr. is still alive and back in town. Despite warnings from the rest of the family, Arthur tries to reconcile with his father believing that the man had a Heel–Face Turn. However, Arthur Sr. is still as rotten as ever and he cons his son out of a large sum of money and then leaves town once again. A despondent Arthur tries to kill himself. A subversion comes from the fact that the Shelbys, being gangsters and killers themselves, do not have an issue with Arthur Sr being a thief but they find it unforgivable that he has no problem stealing from his own family.
- Soap: In order to get out of the mafia Danny has to kill someone, so the mafia will have something on him. The good news is that he gets to kill the person who killed his own father - which is news to Danny, he thought his father died of natural causes. It turns out that his father was also in the mafia, and had been killed by Danny's stepfather Burt when Danny's father tried to muscle in on his construction business.
- The Temptations, "Papa Was A Rolling Stone", in which a family learns the awful, awful, truth from Momma about their father's history of lies, theft, and deception.
Hey Momma,I heard Papa called himself a jack of all tradesTell me is that what sent Papa to an early graveFolks say Papa would beg, borrow, stealTo pay his bills
- In Something*Positive, Rory wrote a letter to his biological father, deciding to keep the profanity-laden response as a reminder of how low he must never sink.
- In Girl Genius, Agatha gets a fairly huge one when she realizes that her mother, Lucrezia Mongfish, is The Other, who was the cause of years of warfare and the mental enslavement of huge swathes of the population. The fact that this revelation comes at the same time as she is being hailed by worshippers of Lucrezia as the Holy Child, and then gets her mother's mind implanted into hers and has her body taken over, just takes everything Up to Eleven.
- Gil got a minor version at some point pre-canon - his father kept his parentage secret from him until he was at least eight, for fear of assassination, and he was badly bullied as a child for not having any family. He gets a small one when he and Tarvek find out that his father is apparently a rural Spark who was killed by one of his own creations and turned into sausages, which isn't exactly the kind of parent you want. Then he finds out that his father is actually Baron Wulfenbach, ruler of most of Europa - who hadn't told him even though he knew the bullying and torment he was going through. And he still doesn't know who his mother is, although If it is indeed Zantabraxus, Queen of Skifander, like Word of God implies, it's going to be an even bigger surprise.
- In the American Dad! episode "Con Heir", Stan's real dad, Jack Smith, reappears after being gone for 20 years. He's eventually revealed to be a jewel thief who tricks Stan into helping him steal art and other artifacts.
- Finn's father from Adventure Time is initially a complete mystery, but when it's revealed that he's alive, Finn is very eager to meet him. He obviously has high hopes that he'll be some kind of hero like Finn himself, despite the fact that it's revealed he is in an inter-dimensional prison. But of course, it turns out he's basically a selfish coward who scams and takes advantage of people as he bums around space, and Finn is devastated to find that he was abandoned and his father doesn't seem to care about him at all.
- Caleb in W.I.T.C.H. is not pleased to learn in season two that his Missing Mom is also the season's Big Bad.