Chiyo's parentage in Azumanga Daioh falls into this. Both Osaka and Sakaki dream of her father being a "cat creature" which is seen in series as a stuffed animal. When scenes are shown of Chiyo interacting with her family, her parents are never seen. Thus, while one possibility is that she has parents like the other girls, but they aren't seen either, the way it's presented tends to suggest that she is either talking to imaginary parents, or that her father really is that cat-creature.
Goshiki Agiri from Kill Me Baby is a ninja, yet most of the actual ninja tricks she uses are either obviously accomplished or purely jokes.
Hayate × Blade: Did Wanko REALLY curse those two girls in her debut fight, or did they just freeze from fear at her sheer creepiness?
Sora No Woto thrives on this. Are the main religions right and "Them" were supernatural beings? Are the ghosts real, or just a hungry owl and a PTSD induced hallucination?
Some of the things Break does in Pandora Hearts fall into this. We've seen him use actual magic to bind Alice right at the beginning. But he also produces things from nowhere (or out of his hat) which could be illusions or could not. And is Emily ventriloquism or something else?
This trope is a major theme in Denpa Onna to Seishun Otoko. The title character, Erio Touwa, believes she's an alien and eventually secludes herself from almost all human contact. Then her cousin Makoto Niwa moves in due to his parents having to work outside of Japan, and he brings her back to reality. She slowly starts to reintegrate into human society, and then a strange girl named Yashiro Hoshimiya appears and berates him for causing her to stop believing in aliens. He constantly ridicules her as well, thinking she's got the same psychological issues Erio went through. At the end of episode 13, Yashiro tells Makoto to move slightly from the position he's standing in. Shortly after he does, a meteor crashes into the exact spot he was just standing in, causing him to wonder if she really was telling the truth about being an alien.
In Berserk, the Hellhound entity that resides within Guts. Its presence being hinted in the early Black Swordsman Arc and having a full physical debut in the Lost Children Arc, fans speculate what the Hellhound is and where it exactly came from. Is it an independent spirit that latched onto Guts during the Eclipse event, or is it merely a trauma-induced hallucination spurred by the traumatic Eclipse? Is the Beast a separate and malevolent force that has always resided within Guts since birth, or is the Beast in fact Guts himself and is just an anthropomorphization of his darker nature? The fact that the the Berserk-verse is very much one of those Clap Your Hands If You Believe realities (in which it could have started out as an abstract idea but then took a life of its own through Guts' constant contact with the supernatural world), we just don't know what the Hellhound is and might never know.
In the Death Note manga's final chapter, it's noted that Mikami mysteriously died in prison ten days after Light's defeat, leading Matsuda to theorize that Near wrote in the Death Note so as to restrict Mikami's actions, enabling Light's conviction. The anime includes no such speculation from Matsuda, and Mikami instead commits suicide on the spot, casting doubt on a supernatural interpretation.
Calvin and Hobbes: Is Hobbes a real person, or (as most people around Calvin think) just a stuffed animal subjected to Calvin's vivid imagination? Careful attention reveals that instead of both being possible, neither is: Calvin could hardly tie himself to a chair, for instance, which Hobbes has done to him (on request)note this was viewed by Calvin's father. so it's not just Calvin's imagination. On the other hand, photos of Hobbes in action show only a stuffed tiger. The best we're likely to get is the author's comment that "Calvin sees Hobbes one way, and everyone else sees Hobbes another way. I show two versions of reality, and each makes complete sense to the participant who sees it."
This comes up with some of Calvin's other apparent fantasies, too. In one series, he creates several duplicates of himself; no one besides him and Hobbes sees more than one Calvin at a time, but his mother seems a bit perplexed at how she keeps finding Calvin in unexpected places. On the opposite side there are also fantasies that have very mundane solutions that are pointed out, such as when Calvin imagines a baseball coming to life and chewing up his bat, Calvin's father points out the mundane idea that Calvin had been hitting rocks with it, despite Calvin clearly being scared...
The Batman villain Scarface, a ventriloquist dummy mob boss, is sometimes teased as something more than a delusion of an unstable mind. The Ventriloquist himself believes that the dummy is possessed by the spirit of a gangster rather than a facet of his own personality; since it was cut from wood of a tree that in the past was used to hang criminals, it is a rather spooky origin for a seemingly mundane puppet.
How "real" Scarface is also depends on the continuity. In some, the Ventriloquist was able to free himself of Scarface's influence via therapy; in others, all it took was destroying the doll.
Global Frequency #5, "Big Sky", revolves around the appearance of a spectral, otherworldly being referred to as an 'Angel', which is powerful enough which drives the entire population of an isolated Norwegian coastal town mad. The team eventually discover a mundane explanation involving the burning down of a local church and resonance around local rock formations which caused sensory overload — but then, after they've identified this explanation, one of them floats the possibility that the appearance of a real angel might have similar effects involving similar probabilities.
This comic run introduces a character named Ezekiel that claims that Peter's powers aren't a mutation caused by an irradiated spider bite but are in fact "totemic" powers carried by the spider which it felt compelled to pass on after being hit by the lethal radiation beam. It was written in a way letting it be totally ambiguous if either this version or his classic origin is the real one, and even suggesting that both might be true to some extent.
When the original Mysterio came Back from the Dead, he appeared to have supernatural abilities, supposedly gained in Hell. Given that he was already a Master of Illusion, it's impossible to be sure how real these powers were, and in the post-One More Day timeline they haven't come up.
Zigzags in Batman The Cult with Big BadDeacon Blackfire, who claims to be a 500-year-old Native American mystic. On one hand, his methods of recruitment are clearly shown to be based on psychology and drugs, just like documented cults. On the other hand, evidence suggests Deacon Blackfire really was immortal. Whether he was a complete fraud or merely a partial fraud is never fully explained.
The antagonist of the Blake and Mortimer book The Sarcofagi of the Sixth Continent claims to be the ancient Indian emperor Ashoka the Great, who first "ressurected" while Mortimer was a young adult to help free India from British rule and later during the "present" to torment the 1958 World's Fair. While it turns out that there is some Legacy Immortality at play since the present Ashoka is actually the daughter of the one Mortimer met in his youth, the identity of the latter is never revealed. Also, they never explain his albino monkey guardians that can be summoned via a puff of smoke.
Punk Rock Jesus reveals towards the end that Rebekah, secretly the protagonist's sister was given a massive dose of drugs and appeared to be drowned as an infant. The characters of Thomas and Sarah briefly debate if her survival was a scientific anomaly or a religious miracle. The reader is left to decide for themself.
The Ultimates began with an unclear origin for the powers of Thor. Is he a real God from Asgard, attacked by a rival god with reality-warping powers? Or just a madman with dellusions of grandeur, who stole high-tech weapons produced in Europe? In the first two story arcs, both options seemed plausible to the reader. The final answer only came at the end of the second arc: he is the real deal.
Until one particular infamous story (regarded as non-canon by much of the readership), this is how the supernatural was handled in The Phantom (the one who lives in the Skull Cave in the Deep Woods surrounded by the Bandar pigmy poison folk). Any time something supernatural was depicted, there was always an alternative "natural" explanation such as magic tricks, illusions or hallucinations caused by fever or gas.
The Annual issue of Transformers: More than Meets the Eye keeping with its close look at Cybertronian religion. Did the ground in Theophany give way by chance, or was it in response to Drift's plea? Was everyone teleported to safety because the Metrotitan's faith in the Cybertronian race restored after Rodimus' selfless act, or was it because he got the energy to do so after some of his mass was displaced? Did Ore disappear because Primus sent him to the Afterspark, or, as an extension of the Metrotitan (having been temporarily resuscitated by him), did he teleport along it? Was it something else? We'll never know.
In Peanuts, does Snoopy's dog house really fly, or is it just his imagination?
Johnny: It's possible I'm quite horrendously insane.
Done 'masterfully' in Reflections. The fate of the dead are left intentionally vague with enough to support either viewpoint.
Hobbes' revised backstory in Calvin & Hobbes: The Series is as ambiguous as can be - Calvin's mom put him in the trap, but she found him laying on their property, looking brand new.
In My Little Mission: Sneaking is Magic, it's left ambiguous throughout the entire story as to whether Snake really was transported to Equestria or whether the entire thing is an illusion happening in his head. It's implied that Ocelot travelled to Equestria too which would mean that Snake really did go there, but it's never confirmed.
Explicitly how Gnome magic functions in Strike Witches Quest. this is doubly hilarious due to the explicit Magitech and Magic A is Magic A of witches.
Loneliness, the first Big Bad of Season 1 of the Pony POV Series could potentially be a supernatural parasite, a Split Personality of Trixie's, a manifestation of Discord's magic, an Eldritch Abomination, Trixie's potential unawakened Nightmare, a Shadow Of Existence attempting to steal Trixie's Light to reconstitute itself, or simply a figment of Trixie's imagination. Support is given for all possibilities and which if any is the actual origin is never explained, either in universe or by Word of God, who intentionally left it ambiguous to make her that much scarier, and she's thoroughly destroyed at the end of the fight with her, so there's no chance for the characters to find out.
Rapunzel: Something brought you here, Flynn Rider... Call it what you will. Fate, destiny... Flynn: A horse.
In Disney's The Hunchback of Notre Dame, it's ambiguous as to whether or not the gargoyles are sentient and capable of movement. It's possible they're just imaginary friends Quasimodo created to deal with his isolation.
Another gargoyle gains life in the climax, scaring Frollo and then breaks.Maybe it was Real After All, maybe was an unrelated hallucination
In The Prince of Egypt, the Egyptian priests' magic is presented this way—they change their staffs into snakes in the middle of a huge Villain Song, with a bright flash that keeps the audience from seeing what actually happens. Them turning water into blood looks more obviously fake, though: they just add some powder that gives it a reddish tint. Of course, the point of the demonstration was to make Moses look like a deceiver.
The Lego Movie has an example that goes beyond the others; Late in the film, it's implied that the whole adventure is just real-life human Finn's playing with his dad's Lego sets- but our hero Emmet is fully conscious and- with some difficulty- capable of moving a little while in the 'real world'.
Films — Live-Action
Nymphomaniac: Joe is possessed by The Whore Of Babylon (but maybe it was only an epileptic seizure after all). She later grows to lead a gang to fight against Love, because love only leads to jealousy... (or maybe this gang was an actual Satanic Cult after all). Having personally encountered demonic forces and been deeply involved with them, Joe has grown into an atheist who do not believe that the supernatural exist... but does this make her a Flat Earth Atheist or someone who has Outgrown Such Silly Superstitions by acknowledging her own mental illness?
The Men Who Stare at Goats: The film never answers if there's real psychic powers or not. The main character does run through a wall at the end...
Pan's Labyrinth has two different interpretations according to whether the fairy world is real or made by Ofelia's imagination. The director believes it's real (well, as real as fiction gets anyway), but has no objection to people coming up with their own interpretations.
Del Toro also says that he deliberately leaves one thing in his movies that can only be explained through supernatural means. In Pan's Labyrinth, it's Ofelia using the magic chalk to get in the Captain's room and retrieve her brother. In The Devil's Backbone, it's the teacher's ghost freeing the children from the room they have been locked in.
In Miracle on 34th Street, the old guy who claims to be Santa Claus never does anything unambiguously supernatural. Even his piece de resistance, finding exactly the thing Susan wants for Christmas even though nobody was sure it existed, might just be a stroke of good luck.
The opening of Indiana Jones and the Temple of Doom: Shiva sent you! Indiana attempts to convince them that it really was a string of wild coincidences that brought him there, alive, despite many, many things that could have killed him if they had shifted by a hair's breadth. Oddly enough, they continue to find the divine intervention plausible. (Later events are clearly supernatural; it's only Indiana's presence that is ambiguous.)
In the Don Knotss classic The Ghost and Mr. Chicken, the invisible piano player who haunts the mansion is later revealed to be a parlor trick by the Gardener, who is organizing a plan to unveil the murderer who killed the house's owners - their son. However, certain other things in the house are more difficult to explain, such as the front door, and at the very ending, when the protagonist and his love interest are being wed, someone starts to play the Piano in the tune of the ghostly theme - someone who isn't there..
Fantastically done in K-PAX, where the film never truly answers the question of whether the main character, prot, is an alien or just a very convincing delusional named Robert Porter who suffered a psychotic break after his family's murder. The audience is left to wonder, and the possible consequences of either answer end up surprisingly heartwarming. Though the fact that he can apparently see infrared light makes the delusion pretty convincing.
This is the whole point of A Serious Man, which is extremely stubborn when it comes to answering Larry's questions (and ours) as to whether the hand of God is at work in his life, or if there is a purely rational explanation for everything (as he wants to think).
Wonderfully played in the climactic final confrontation between Sherlock Holmes and Lord Blackwood in the movie starring Robert Downey Junior, where after dissecting every one of Blackwood's "magic tricks" as fakery, he comments that if Blackwood actually believed in his own sorcerous rites and the dark things he'd invoked, then he'd know what waited for him after death. Cue Blackwood accidentally falling to a hanging death, just as a crow flies past.
The film Dracula's Daughter, despite being advertised as a sequel to the famous Bela LugosiDracula film, remains maddeningly vague on whether the title character actually is Dracula's daughter. She's never seen doing anything overtly supernatural like Dracula in the first film, and ultimately dies from a stake in the heart, something equally lethal to both humans and vampires.
Vincent and Jules being miraculously saved from several gunshots at point-blank range in Pulp Fiction.
Marvin:"Man, I don't even have an opinion."
Hot Tub Time Machine repeatedly draws attention to this trope and straddles a strange line between playing it straight and parodying it in the person of the Hot Tub repair man, who may just be a repair man, or may be some sort of Time Police setting the time travelers on their way. Jacob even lampshades it, by noting that the repairman's words perfectly support either theory, and asks if it would kill the repairman to just give him a straight answer.
Below: Were the strange apparitions the result of high CO2 levels or vengeful spirits? On the one hand they clearly weren't Dead All Along, on the other something other than guilt brought them back to the site of the hospital ship they accidentally torpedoed and deliberately covered up...
In A Matter of Life and Death: did his head injuries cause his visions? Or are the angels really discussing the proper thing to do with him?
Black Death ends like this, with the witch taunting the protagonist that her "black magic" was really tricks and misdirection she used to control the villagers. This is particularly stinging because the protagonist had earlier killed his love interest after she had been "raised from the dead" as a mindless abomination... the witch implies she was merely heavily drugged and was never dead in the first place. It's left ambiguous as to whether this is the truth, or if the witch was simply lying to the protagonist to get him to lose his faith in God.
It's possible "La Femme" from Inside is some kind of ghost.
In Don't Go in the House the Villain Protagonist hears voices that we assume are just auditory hallucinations, though as he's dying they call him a failure and say they'll find someone else. Before the credits role, another abused little boy is shown hearing similar voices.
The titular highway of Interstate-60. When Neal asks how he can be driving down a highway that doesn't exist, he's literally offered several possibilities.
Grant: Maybe it's another dimension, maybe you're in a coma, maybe you're hallucinating, or maybe, just maybe, you're dead.
Neal: So, which is it?
Grant: What do you want from me, kid? I just gave you a bunch of answers, all of them reasonable. You want an answer? Pick one!
Big Trouble in Little China is filled with magic and monsters, but before the final battle, Egg Shen gives everyone a drink that can make them "see things no one else can see, do things no one else can do." Afterwards, Jack Burton is still Wrong Genre Savvy, but Wang Chi manages to kill a storm god. Did the potion actually help?
Cassandra Nightingale in Hallmark Hall of Fame's The Good Witch and its sequels. Usually, it's made clear that her "magic" is really Granny Weatherwax-style "headology"...but each film has at least one or two little moments (e.g., brooms appearing just when she needs to sweep up, doors opening of their own accord, plants in her garden seeming to shift to trip up trespassers, etc.) that hint that she could have real powers.
In Eve's Bayou, the main character uses voodoo to try and kill her father for hurting her sister. He does die at the end, as a direct result of Eve's actions, but it is never explained whether or not the voodoo had a hand in what happened.
Depending on how you interpret the eye protecting "true magic" in Now You See Me.
The Lone Ranger somehow survives the attack on his team. The horse tells Tonto that the Ranger died and came back to life. Tonto tries to convince the 'spirit horse' to bring his brother back instead.
Tonto also believes Cavendish isn't an ordinary criminal, but a Wendigo. This is the explanation for why the Lone Ranger uses silver bullets. Cavendish being a cannibal doesn't help things...
The Lone Ranger not only gets a psychic vision from picking up a piece of Cavendish's silver, but despite not having fired a gun in eight years prior to his "death", he manages to repeatedly pull off ridiculous trick shots. He finally just goes with it.
In the 2000 movie Waking The Dead, Fielding's girlfriend Sarah is killed in a car bombing, but he keeps seeing her in crowds and hearing her voice. She eventually comes to his office late at night to say goodbye and Fielding doesn't see her again afterwards. Either she was a ghost, she faked her death and went into hiding, or Fielding's grief made him mentally unbalanced. None of these scenarios are proved or disproved.
Mr. Cracker, the Bartender:Well, there's two schools of thought, sir.
In Big Fish, most of the things Edward Bloom says in his stories turn out to be are exaggerations based on things that actually happened (for example, Karl was indeed a giant, but not nearly as big as Will imagined him). However, we never learn wether seeing his own death in the witch's eye was real or not, as we never hear him say what happens.
In Stalker, it's never made clear how much power, if any, the Zone actually has.
Selina Kyle's 'powers' in Batman Returns. The supernatural would definitely explain how a mousey assistant could gain the ability to actually hold her own against Batman and survive fatal falls and several gunshots. Then again maybe her brush with near-death simply pushed her over the edge and turned her into a combination of The Determinator and The Unfettered, making her run on sheer will power.
In The Dark Knight Rises, Ra's Al Ghul's drops in to have a chat with Bruce. It could easily be a hallucination, but Bruce gets relevant information from it that he didn't know. It would be easy to argue whether it was a hallucination or if Ra's actually is immortal. Though it does turn out that said information is false, so if Ra's was indeed around for that conversation, he's quite good at bullshitting.
Lillith of Hansel and Gretel (2013) claims to hundreds of years old, and repeatedly makes characters hallucinate. However, there's no real proof to her claim of longevity other than a few photographs she claims depict her, and all of her tricks seem to be done via drugs.
In John Hemry's Paul Sinclair novels A Just Determination and Burden of Proof, after the death of men, the crew believe that the ghosts are haunting them. When two junior officers are in free fall, a screw starts to move. The engineer explains that vibrations could cause that.
When Frodo and Sam have climbed down the rope given to them by the elves, it comes free. Frodo says the knots must have given way, and Sam thinks that it came when he called it. Neither one thinks either explanation very good, but both conclude that it had to be that way because nothing else would have worked. Later, a third possibility is implied, when Gollum mentions burning his hands on elven rope but gives no details of when and where this happened.
Other instances: Was Frodo divinely appointed to be ringbearer or was it blind luck? Did supernatural intervention block the pass of Caradhras or did they just get there in a bad season? When Frodo heard that voice on the steps of Amon Hen, was that God or Gandalf or just his own good sense kicking in? Etc.
In the case of Caradhras, it's implied in the books that Caradhras (the mountain) has some control over its own storms, and dislikes dwarves. In the movies, they replace this by explicitly showing that Saruman amped up the storm to try and force them to come south through the Gap of Rohan, right by his territory.
Invoked when some elves of Lothlórien reveal that what is magic and what is mundane is a question of perspective in Middle-Earth, as the elves themselves have no concept of "magic" — a lot of things that are natural to the elves are considered magic by mortals, simultaneously lumping it together with methods employed by Sauron, which the elves will never use.
'For this is what your folk would call magic. I believe; though I do not understand clearly what they mean; and they seem also to use the same word of the deceits of the Enemy. But this, if you will, is the magic of Galadriel.
Tolkien's other works also feature this:
The Children of Húrin: Was Túrin's terrible life because of Morgoth's curse or because he doesn't know when to swallow his pride?
The Silmarillion: Did the Sons of Fëanor really have no choice in pursuing their Oath, or are they only saying that to justify their horrific actions to themselves?
In Dorothy L Sayers's Nine Tailors, one of the bells is "known" to have killed two evil-doers in the past. At the end of the book, Lord Peter Wimsey realizes the victim was also killed by the bells, in this case by being in the belltower during a long peal, which may have been a third instance of the bells dealing out justice. (His arrival at the beginning was heralded as something that might be called chance.)
In Murder Must Advertise, Dian regards the Harlequin as a lucky charm because she wins twice at horses, and afterwards is good at cards. The narrator says this might be just her determination.
Amelia Peabody often dreams of her old friend Abdullah, after he is killed. Only he looks young now, and he was old when they met... He offers promptings, rather than clues, about the mystery of the moment ... mostly. She comes to believe she's really meeting her old friend in the afterlife. Her family are not so sure, though their skepticism is showing signs of erosion by the end of the series.
In Deus Encarmine, Rafen remembers, in his Back Story, how he had once thought he had seen Sanguinius in lights in the sky; perhaps a trick of the mind, through fatigue and despair, but it reminded him that the Pure One was judging him and caused him to rally.
Again in Deus Sanguinius, after psychic attack by Inquisitor Stele has driven him to suicidal depression, Rafen flees. He stumbles on the mediation chamber he had made for himself earlier — explicitly described through the guiding hand of the Emperor, muscle memory, or blind chance.
In Black Tide, Rafen wonders whether his capture was the guiding hand of the Emperor or capricious fate. (If it's the first, he will do his duty; if the second, to hell with fate, he will do his duty.)
In A Connecticut Yankee in King Arthur's Court, all of Merlin's "magic" relies on fakery and a gullible audience, and he's strongly implied to have no actual powers at all. But at the very end, he casts a spell that really works, and it's never stated if he found some scientific way of pulling it off or if he really did have some magical powers after all.
In Kate Seredy's The White Stag it is never clear if the forces that brought the Huns to the new land and the white stag are a higher being fulfilling prophecies, or just plain luck.
In Graham McNeill's Warhammer 40,000Ultramarines novel Black Sun Dead Sky, when Uriel is trying to convince the Unfleshed of his friendliness, their icon of the Emperor lights up — either a mechanism jogged by Uriel's movement, or a miracle.
In Nightbringer, the Almost Dead Guy Gedrik should have been dead. Uriel takes what appear to be ramblings very seriously: he thinks that being so near death may have given him visions.
Charles Brockden Brown's Wieland toes the edge of this trope. Though it is revealed that the voices which Wieland hears have a physical source, the fate of Clara and Wieland's father is still ambiguous: it was either the inexplicable wrath and majesty of God, or spontaneous combustion. Which people did believe in in those days!
Gene Wolfe's Soldier of the Mist and Soldier of Arete. He, and those around him, think he's been cursed by the gods to forget everything every night. Even the gods speak of it when they talk to him. We, on the other hand, have enough evidence about his head injury to conclude that that may explain both the amnesia and the hallucinations.
Gene Wolfe's Book of the New Sun. Many of the events Severian experiences are open to interpretation: are they magic, advanced science, divine intervention, simple trickery or misunderstanding by the narrator?
In The Dresden Files, Harry's Church Militant friend Michael frequently receives very beneficial "coincidences." At least, Harry believes it to be coincidence. Michael is quite certain it isn't. Harry's repeatedly stated position is one of absolute neutrality — as he describes it, Theological Switzerland. He acknowledges that Michael possesses a power unlike Harry's wizardry, but debates just how powerful Michael's divine protection and ability seem to be at times.
In Grave Peril, Father Forthill just happens to knock on his door at the same moment Michael needs to leave his house, because Forthill's car just happens to have gotten a flat tire nearby, freeing Michael to leave his younger kids with someone he trusts.
At a few points in the books, Harry debates this to one of the other Knights — who paradoxically, is a confirmed agnostic — and Harry's taking the side of Christianity.
In Death Masks Michael, wearing heavy armor and unconscious, and Harry are in a river when crime lord Marcone tosses Harry a line and pulls both of them to safety. The line turned out to be the Shroud of Turin, burial cloth of Christ. A 2000 year old piece of cloth gaining the tension strength to withstand two heavy men being pulled with it out of rushing water and never tearing. Yeah. Just a coincidence and good craftsmanship.
In Small Favor, a civilian under attack by a monster is praying to God. Cue Michael.
Yet another time: Michael is mysteriously absent during Molly's prosecution for the use of Black magic, Harry's plan to prevent her execution relies on Michael having been sent to just the right place for "coincidence" to work in his favor. Micheal did indeed as he saved three of the more lenient Senior Council members, Captain of the Wardens, and her training recruits from certain death. Arriving at the trial in time to take back their proxy votes from the more hardline leader.
Michael: So what you're saying is, you took a leap of faith? Harry: No, I took your leap of faith, by proxy.
Another time: In Harry's darkest moment in Changes, Sanya manages to show up again just after an old woman screams "Oh, God in Heaven, help us!" Sanya claims it was probably just a coincidence.
Every single Bailey School Kids book is like this. Is the authority figure supernatural/villainous, or are the kids just jumping to conclusions?
Edward Eager's books are usually about children who find some kind of magic object and have adventures, but in two of them — Magic or Not? and The Well-Wishers — the main characters never find out if the wishing well was really magic or if everything that happened was just coincidence.
Marcus Pitcaithly's The Hereward Trilogy is full of this trope. Hereward's "enchanted" sword and hauberk, the mermaid/ghost/whatever that appears when he's returning from Flanders, the will-o'-the-wisp that guides his gang back from the raid on Peterborough, the Toadmen's rings and their power over animals, the Guardian of Wandlebury, Gunnhild's witchcraft, his repeated apparently meaningful dreams... Also Lysir, who may actually be a god in disguise. All of them could have natural explanations, but it's left open.
In Castle Roogna, a ring claims to be magical, a wishing ring. When Dor makes a wish on it, it answers, "I'm working on it." Every wish made on it comes true through outside factors — except that every wish made on it does come true, and it never claimed that it could pull off instantaneous wish granting.
In Sharon Shinn's The Alleluia Files, the revelations about the spaceship do not shake all the characters' faith. Some still think that their lives, and these events, had been divinely guided. Indeed, Tamar, raised to disbelieve, announced that she had come to believe.
A Song of Ice and Fire appears to have a clear relationship between the existence of dragons and that of magic. The dragons died out before the start of the series, with only a few dormant eggs left behind, and no living dragons = very limited magic. So the series starts with little magic (although some of it seems rather powerful) and until Daenerys hatches her dragon eggs most "magic" is faked, lucky, or misunderstood. After Dany hatches the dragons, the lines get blurred; while more true magic is beginning to occur and is increasing in frequency and power as the dragons grow and Daenerys gets closer to Westeros, there are still fakers, lucky people, and ignorant people out there. Some examples:
The Red priests and the priests of the Iron islands have always had a "miraculous" technique of restoring life to the recently dead or drowned that is initially very clearly described as a variant of modern CPR and rescue breathing, making it entirely mundane... until, in book four, they begin using the same techniques to resuscitate people that haven't been breathing for hours or, in a few cases, MONTHS.
There is one particularly confused Red priest who used to light his sword on fire with oil as a party trick, then one day accidentally tried it without the oil and found it worked anyhow.
In A Storm of Swords, Stannis and Melisandre perform a ritual which will supposedly cause the deaths of the other three surviving kings, Balon Greyjoy, Robb Stark, and Joffrey Baratheon. By the end of the book, they're all dead... but they all died separately, from completely unrelated causes. More importantly, the events leading to the deaths were, in two and possibly all three cases, set into motion well before Stannis even performed the ritual. Tywin Lannister had already plotted to kill Robb, Margaery and Olenna had been making provisions for Joffrey, and while the cause of Balon's death remains somewhat unclear there is a long, long list of people who might have been planning to take a shot at him - not least Euron Greyjoy, who conveniently appeared just after his death to claim the throne. To make things more confusing, Melisandre has definitely performed legitimate magic prior to the ritual, most notably sorcery that was definitely the cause of Renly Baratheon's death. According to A Dance with Dragons Melisandre's powers are a combination of tricks and legitimate magical power. Since the rebirth of the dragons, she's been using more of the latter kind.
There are a lot of cases where something might be magical, or it might just be a coincidence; in particular most prophecies are entirely self-fulfilling. Most notably among the point of view characters is Cersei, who was told that she would be supplanted by a younger, more beautiful queen, and betrayed or killed by her younger brother. Nothing has come of it yet, but she could very easily fulfill it all by her lonesome; there are three beautiful potential queens (Margaery, who married King Renly and then King Tommen, Sansa, who could yet become Queen in the North, and Daenerys, the last claimant of the old Targaryen dynasty across the sea who calls herself Queen and has dragons) who have good cause to hate her, and she has been absolutely vile to bothher brothers (remember that Jaime is the younger twin by a matter of seconds,) so that now one really wants to kill her and will very likely make an attempt when their paths next cross, and the other may yet cause her death by inaction, having ignored her pleas for his help in favour of fulfilling his oath to Brienne.
Psychic Dreams for Everyone! Except that it's really really hard to tell the difference between a true psychic dream and a hallucination, especially since most psychic dreams occur while characters are badly injured/feverish/etc. (such as Bran's dreams of the three-eyed crow during his coma, or Jaime's visions regarding Brienne during a traumatic injury and subsequent severe infection. While the former's visions seem to be genuine, the latter's might yet swing either way—though they seem to be mundane, as the character they were dreaming of might be dead.)
The most borderline case of a possibly psychic dream? Euron Greyjoy mentions that he dreamt a crow told him he could fly in a dream, which is similar to a dream another character had that turned out to have a magical origin.
The supposedly "cursed" castle of Harrenhal. Most educated characters in the series dismiss the curse as nothing more than the superstition of ignorant peasants. However, in world where most of the great strongholds have belonged to the same family literally since pre-history, nine different families have controlled Harrenhal. Moreover, most of the characters who have been in Harrenhal since the series started have come to a bad end. All-in-all, no matter how much people may dismiss the curse, they aren't exactly eager to claim the title "Lord of Harrenhal" either.
In Dan Abnett's Gaunt's Ghosts novels, Larkin's scope. It appears to show him things. Except that he's several cards short of a full deck.
His best example comes from the story of the Angel in Ghostmaker. In a mission to sneak into a Chaos-held city and snipe its leader, Larkin loses it and abandons the mission team. He holes up in a room high up on a tower with a statue of an Imperial Angel - which he imagines talking to him, convincing him to do his duty and giving him a strip of cloth to help steady his aim. He ends up taking out the Chaos warlord, then passes out. When he comes to, other Ghosts are helping him up, and Angel is just a statue again - but his long-las is sitting in the corner with a band of silk tied to it.
There's also the... impressive performance of Saint Sabbat in Sabbat Martyr. On the one hand, she has a small fortune worth of the best armor and weaponry the Imperium has to offer. On the other hand, she comes by the title "Saint" honestly. (On the gripping hand, she solo-kills a Baneblade and duels and kills a Chaos warlord.)
Much of the premise of House of Leaves is very heavily based on this trope.
In K.J. Parker's The Scavenger Trilogy, after he loses his memory, all of Poldarn's actions are consistent with being just a unwittingly malign man, mired in circumstance and human nature or being the God of Destruction. Or possibly the human agent for a group mind of crows. Or both.
Pretty much every one of Terry Pratchett's Discworld novels dealing with the witches positively dances on this line. Witches obviously use magic. They also use "headology", which is essentially making people think they're using magic. Which one they're using at any given time isn't always clear. And then Granny Weatherwax gets annoyed at people's gullibility for assuming she's doing high-level magic when there's actually a perfectly mundane explanation, even though she and the reader know she was using magic and the mundane explanation is wrong. ("That's not the point. I might not have been.")
Near the end of Making Money, Moist is in a jam, and decides to try praying to Anoia, Goddess of Things Stuck In Drawers. Later in the book, after he is saved from a mugger when the man's dentures explode — albeit after years of abuse, he decides to make a thanks-giving offering of a really big ladle.
In Cryptonomicon, also by Neal Stephenson, Enoch Root does something to fix Amy's leg after she gets shot with an arrow. Neither of them are willing to say what he actually did. Enoch himself also qualifies for this trope, as he appears in both Cryptonomicon (set in WWII and the modern day), and in The Baroque Cycle. It's never explicitly stated if it's the same Enoch, or two men with the same name.
Harry: Is this all real, or is it just happening in my head?
Dumbledore: Of course it's all happening inside your head, Harry. But why on earth should that mean it's not real?
Similarly, the Deathly Hallows themselves - are they genuinely mystical artefacts of Death himself, or merely incredibly powerful magical items invented by the Peverell brothers?
Also, Professor Trelawney is generally believed to be a fraud who enters the occasional genuinely prophetic trance, but almost every "fake" prophecy she makes comes true in some sort of way. Some of them can be explained as cold readings, but sometimes she comes suspiciously close to the truth - at one point she reads the cards in a way recognised by the reader (though not her) to identify that Harry's close by and in a bad mood; and at one point she gets Harry's birth month about as wrong as possible, but it's perfectly accurate for Voldemort, a part of whose soul is sitting in Harry's head.
As well as Harry dying young (if only for a moment).
Though Trelawney makes just as many predictions that don't come true: classes are never canceled due to a flu epidemic and Neville isn't late to class on the second day.
An early book, The Ghost at Dawn's House, ends with Nicky Pike being responsible for most of the strange things that Dawn observed—but not all of them. The ending of the book leaves open the possibility that Dawn's house really is haunted.
Another example would be Mary Anne's Bad Luck Mystery.
Also, the first book in the Little Sister series, where the only undebunked evidence Karen has at the end is that she saw the lady she thinks is a witch flying on a broom... and that might have been a dream. A later book in the series had Karen suspect that Mrs. Porter's granddaughter, Drusilla, is also a witch. Drusilla later admits she's not, but says she's never been sure about her grandmother ...
In Kate Seredy's The Singing Tree, the cat acts ill in the cart, so they stop by a hospital where they learn she's having kittens. They wait, and Kate and Lily help the nurse bring soup to the wounded. Which is how Kate sees the amnesia case and realize it's her Uncle Marton — shouting that at him jogs his memory lose. When arguing that they should take him home despite his lack of papers, one argument is that it was obviously Destiny and who are they to argue with destiny.
In Warrior Cats, during a big battle over leadership in WindClan, lightning strikes a tree, causing it to topple over and form a bridge to a nearby island (which would then be used as important neutral ground for the four Clans). It also crushed the cat attempting to usurp leadership. The cats (and some of the fans) see this as far too convenient to be coincidence, and believe that StarClan directed the lightning. On the other hand, the cats have seen StarClan's influence in things they had nothing to do with before, and StarClan have also stated that they have a strict non-interference policy.
At least in the first series, it's arguable whether or not Star Clan exists at all. Maybe Scourge really is so strong that he can drain a Clan Leader's 9 lives in a single kill...or maybe everyone only gets 1 life, and the only difference is that a Clan Leader is harder to kill because of his or her experience and talent.
In Andy Hoare's White Scars novel Hunt for Voldorius, Kor'sarro is not sure how he recognizes that Nullus is a daemon; intuition, or maybe being near another daemon.
"Mitra has spoken," replied the princess. "It might have been the voice of the god, or a trick of a priest. No matter. I will go!"
In "Shadows In The Moonlight", Olivia's initial conviction that statues in a certain hall came to life settled down to the view that it was this trope when she had to rescue Conan from Pirates there. (Turns out to be Real After All.)
Was it some trick of the moonlight that touched the eyes of the black figures with fire, so that they glimmered redly in the shadows?
Samuel Delaney's Dhalgren: all sorts of strange things happen, ranging from mildly unsettling (several characters get exactly the same scratch on the thigh), through the absurd (the city's geography seems to rearrange itself), to the absolutely terrifying (the sun rises one day and takes up half the sky, and then the next day everything is back to "normal"). None of this is ever explained, so it could be the Unreliable Narrator, or it could be something far weirder.
In Jo Walton's Among Others, the main character is able to see supernatural beings and work magic. However, it is somewhat ambiguous as to whether the beings she sees are magical or the product of a lonely teenager's imagination, at least in the beginning of the book. The magic in this book mostly works in a subtle manner through coincidences that leave plenty of room for doubt as to whether the results were really due to magic after all. For example, the character tries to cast a spell to find a karass or Nakama because she can't find anyone at school she can relate to. The next day she gets just the kind of result she was hoping for when a librarian mentions a local science fiction book club and asks the protagonist if she'd like to join. The protagonist herself wonders whether this was a result of magic or coincidence as the book club had existed for a while before she'd ever heard of it.
Many of Zilpha Keatley Snyder's novels ride on exactly that variation of the trope. It's especially noticeable in The Changeling and The Witches of Worm.
In Poul Anderson's The Devil's Game, what exactly is the title "devil"?
In Henry James's The Turn of the Screw is an early example: are the ghosts real or a figment of the governess's neurotic imagination?
In Bernard Cornwell's Warlord series the narrator maintains that all the magic shown by Merlin, Nimue and others have possible natural explanations but that they could also be genuine. Further confusing things is Nimue's admission that some of her and Merlin's magic is indeed just trickery while other parts are very real. During the course of three books the series plays with the existence of magic just about every way possible, whether it be that magic seems to be real, seems to be fake, or is left ambiguous. And sometimes a spell or magic artifact will appear to work powerful, genuine magic, only to completely fail to work at all later. Ultimately the first two books lean towards things being mostly, if not entirely "mundane", but the last one has several events that are really difficult to explain without magic.
Bernard Cornwell really likes this trope, with The Saxon Stories pulling it every now and then, with the rune sticks being disturbingly accurate and Uhtred's shadow walker antics.
Even possibly Sharpe providing an example with the Gonfalon of Santiago, though the last leans very much on the mundane end of the spectrum.
In the Johnny Maxwell Trilogy, the question of whether the ScreeWee, the Dead and the time travel are all real or whether Johnny is, as Wobbler tactfully puts it, "mental", is resolutely unanswered until the final scene of Johnny and the Bomb, when Kirsty remembers it too. There is evidence supporting the former view, but it could all be explained away if you tried hard enough.
In C. S. Lewis's Till We Have Faces, it's unclear whether certain events are caused by the wrath of the gods or whether it's just coincidence being misinterpreted by a superstitious people. Until the narrator sees a god with her own eyes.
In Jack Campbell's The Lost Fleet Captain Desjani insists that Geary is guided by the living stars.
In L. Jagi Lamplighter's Prospero Regained, Gregory recounts a vision that changed him — and then immediately dismisses it as a delirum, albeit one that made him think.
In L. M. Montgomery's The Blue Castle, Valency offended her mother, who sulked. Then she got the letter from the doctor, which gave her her diagnosis of fatal illness. She thought the matter providential, because otherwise her mother would have asked whether there were any letters and read it; now she could keep it a secret.
In The Brothers Karamazov, Ivan's famous dialogue with the Devil might be pure feverish delirium, or might be a genuine vision. You're the reader: you decide. This is foreshadowed by his own parable of the Grand Inquisitor, when Alyosha (tellingly) protests that the prisoner could not have actually been Jesus, and Ivan just says it doesn't matter either way.
In the book version of The Exorcist, the viewpoint character is able to come up with a mundane explanation for all of the goings-on. Some of them are more than a bit of a stretch, but it COULD all be explained rationally. In the film adaptation, on the other hand, it's pretty tough to explain away the levitating bed....
In Jack Campbell's The Lost Stars novel Tarnished Knight, Iceni considers the prospect of Drakon's failure at one or more ISS site. This will give her the choice of letting ISS endanger her and bombarding from orbit, causing grave harm to many civilians in the area. Despite not believing, she prays to the living stars for guidance. Almost immediately, the displays light up with his success. She tries to convince herself that it's a coincidence, but wrestles with it — and there's, of course, no evidence either way.
Marcus Pitcaithly's Hereward Trilogy contains many, many examples of this trope. Are the apparitions at Frey's temple real or hallucinated? Does Brainbiter have real power, or is it just a Cool Sword? Are the Toadmen's powers over animals real or not? Are the will-o'-the-wisps which guide the outlaws across the Fens a natural phenomenon or sent by St Peter? Is the Guardian of Wandlebury human? Does Gunnhild really have magical powers? And the unanswered question that runs right through the whole trilogy: is Lysir just a man, or is he actually Woden?
Jacqueline Wilson did this in two of her early novels. In The Power of the Shade, the heroine becomes obsessed with the idea of witchcraft after a friend introduces her to the concept, and slowly comes to believe that she really has magical powers. In The Other Side, a girl suffering from severe personal trauma believes that she can astrally project. In both cases it's left open as to whether or not these powers are real.
The Cat Who... books do this with the powers of the eponymous cat, Koko. Does Koko somehow know when someone close to Qwill is in danger and able to psychically intuit who the murder is? Or is Qwill just mistaking ordinary cat behaviour for mystical powers? In favor of the "magic" theory is the fact that Koko has done this so many times over the course of the series (him yowling once at the exact moment someone from Moose County is killed may be coincidence, him doing it a dozen times seems unlikely). In favor of "mudane" is the fact that the characters rarely manage to predict anything from Koko's clues, and the cat's "brilliance" is mostly revealed after the fact when the killer has been unveiled by other means.
A lesser example in the same series is Mildred Hanstable's Tarot readings. They are vague enough that there's no proof Mildred can predict the future but almost always prove accurate.
In Andre Norton's Ice Crown, Niles Ismay had an ancestor who slightly escaped Psychocrat conditioning and passed down stories. As a consequence, he, unlike most people on his planet, can understand Roane's story about the conditioning machinery. He thinks it must be destiny; she's less convinced, it's just chance.
Set in a post-technological world, Gene Wolfe's The Book of the New Sun challenges readers to think about whether events are mundane, magical, theological or technological in nature. For example: the Claw of the Conciliator: miracle-working religious relic, magic feather, alien device?
A Christmas Carol leaves it ambiguous as to whether Scrooge's visit from the three spirits was real or simply an elaborate hallucination.
Life of Pi eventually sets up one of these: Pi tells the insurance company representatives two stories about his survival in the Pacific after a shipwreck, one involving sharing his lifeboat with a tiger and a monstrous Garden of Evil floating island made of algae and trees that eats people and the other just involving Humans Are the Real Monsters. It's not clear which one is true, though Pi argues that the insurance reps should believe the former because it's a better story. In the end, they do choose to believe that it was Real After All.
Ripred points out that Sandwich's prophecies may well just be coincidence or self-fulfilling, and he doesn't believe in them. They seem to be pretty accurate, but only after a book of trying to decipher them and you can see how they could be reinterpreted to fit the latest explanation.
Mrs. Cormaci, who tends to send just the right objects at just the right times and who gives tarot readings. Gregor at one point wonders if she can see what he needs in her tarot cards, and given that psychics exist in this series, he could be right.
The ghosts in Sonic The Hedgehog In Castle Robotnik are never confirmed one way or another. Sonic insists that they're just special affects but the author goes out of his way to say that they must be extremely good special effects.
A huge white blob of supernatural (or perhaps special effect-ual!) force screamed out across the room, blew apart the ghost standing in the doorway...
In Joe Haldeman's short story, "The Monster," the narrator, Chink, a Vietnam vet, calmly and sanely relates his story of being a LURP in 'Nam and watching a glossy black humanoid creature tear apart his patrol-mates. But Chink is telling the story (presumably) to a psychiatrist in a mental institution, as an explanation as to why he slowly and brutally murdered an emigrant from Vietnam — the man he believed to be the monster. At the end of the story, we read a coroner's report that details Chink's death, allegedly from ripping out his own heart with his bare hands. We're never quite sure whether the titular "monster" was real, or just a figment of Chink's imagination.... or whether Chink killed himself, or the monster got him in the end.
Live Action TV
The Darker and EdgierBattlestar Galactica showed characters with clear religious, atheistic and agnostic views. Much of the Story Arc dealt with whether the gods or God were directly leading the remnants of humanity to their new home, or whether coincidence was just a matter of their reality. By the series' final season, the reappearance (and then sudden final disappearance) of an Angel Unaware, as well as a final scene that showed two people, images of main characters that had haunted their counterparts throughout the series, in the modern Earth, 150,000 years later, as fans questioned if the images were hallucinations or technological constructs. The show ended with a significant lean towards the supernatural.
A popular Christmas Episode trope for sitcoms is a "Is Santa Claus real?" story arc, and something mysterious happens that makes the characters think, "Wait... how could that have happened unless Santa Claus is real," or they hear the faint sound of sleigh bells in the air, and so on.
Community has featured malicious robots, ghosts and evil alternate reality versions of the main characters. In all cases it's unclear whether the supernatural elements exist only in the characters' imagination.
The show Mysterious Ways bases its entire premise on this, with a quirky teacher wanting to find a "smoking gun" of supernatural activity but always ending up with plausible but unlikely alternate explanations.
The Eerie Indiana episode "Heart on a Chain" is the only one in the series that never answers its mystery. A shy, terminally ill girl has a crush on a devil-may-care boy, who dies in a freak accident. A heart transplant from his fresh corpse saves her. She then begins acting increasingly bizarre (with a lot less self-control). It is left completely unclear until the end whether his heart's personality has taken over hers (as the Agent Mulder believes), or whether guilt has made her not herself.
The Twilight Zone TOS episode "The Thirty-Fathom Grave". A U.S. Navy destroyer crew investigates a strange knocking sound coming from a submarine sunk years earlier. One of the ship's crew escaped the sinking sub and feels Survivor Guilt: he thinks his old crew is angry at him because he didn't die with them. At the end it's revealed that an object inside the sub could have been making the knocking sound.
Also the episode "The Grave", apparently based on a similar well traveled urban legend. A cowboy in the Old West visits the grave of his enemy on a bet, the dying man's own last words having been an assurance that if he went anywhere near the grave, the dead man would reach up and grab him. As proof, he has to plant a dagger into the plot. When he finally musters the courage to do so, you can't see what's happening but * something* snags him and he goes down stiffly, mostly off-screen. The next morning his corpse is found there by the townsfolk. He had had a heart attack and the dagger was pinning his garments to the ground, perhaps having been blown into his path by the wind, causing him to have mistaken the situation for the obvious supernatural substitute when he found himself snagged upon trying to turn away. But one of the people observes that "the wind was blowing in the opposite direction". The closing narration says that it's up to us to decide what to believe.
"Nick of Time" had its protagonists consider whether a penny fortune-telling machine could truly answer any yes-or-no question correctly, or if it was merely on a lucky streak. People who continue to believe in the machine are shown to stay in town and continue feeding in pennies for fear of their lives. Is it only paranoia, or does the mystic seer use real power to gain addicts?
Babylon 5 usually went with First One technology for its 'supernatural' effects, but a couple of episodes are more ambiguous. Neil Gaiman's fifth season episode "Day Of The Dead" leaves it ambiguous whether the dead people that came back for the night are a result of Brakiri telepathy or the genuine article. At the end, it seems to come down on the side of the supernatural.
In Voices in the Dark: Over Here story of The Lost Tales follow-up has a man who claims to have been possessed by a demon on his shore leave on Earth. He is able to know intimate details about people, but since telepathy is a well-known phenomenon in the 'verse, it's not that surprising. He is also somehow able to get people to smell different things, although that could also be explained by some form of telepathy (i.e. they only think they're smelling it). Lochley definitely believes him, though, and makes sure that the exorcism takes place on Earth (if it had taken place in space, the demon would be free to roam the universe).
The entire point of Cupid, the 1998 version, was to be ambiguous as to whether Trevor was genuinely Cupid, or crazy. The 2009 version likewise fits with this trope.
One memorable Buffy episode featured a demon that caused Buffy to hallucinate herself in a mental hospital. Her mother was still alive, her parents were still together, and she was diagnosed as paranoid and delusional. The episode never really explained if everything we've ever seen in the show is real, or all part of a sad girl's hallucinations. (Or both. It's not the first time we've seen alternate universes on Buffy: maybe there's one reality where everything we see happens, and another where Buffy hallucinates it all.)
In the episode "Amends", a snowfall prevents Angel from killing himself. The chances of a blizzard in Southern California are incredibly small, but there's still a chance that it was entirely mundane. In the Angel spinoff series it's further hinted at that the Powers That Be may have intervened, but it's still left pretty ambiguous.
Christmas episodes seem to be a breeding ground for this trope. It happens in a Christmas episode of Roswell when Max heals an entire children's cancer ward. Possibly averted given Max's abilities, but the trope is largely played up in the show.
ER had an episode where a jolly, bearded toymaker comes in... and has mysteriously vanished by the end of the episode.
ER also had another Christmas episode where Benton offhandedly touches a blind hypothermia patient's forehead, and said patient suddenly (and temporarily) regains his sight, causing several homeless people to station themselves in the ER to get "healed" by the "miracle worker". Benton predictably brushes their claims off with annoyance, but keeps getting his claim that it was just a coincidence weakened by random occurrences like a broken vacuum suddenly starting up again when Benton passes by. At the end of the episode, Benton still won't address the issue, but is told by Neurology that no one can find a medical reason for why the man got his sight back for an afternoon.
Cheers subverted this when no one in Norm's Department Store Santa class could identify the realistic Santa from their class, which caused Frasier (in full Ebeneezer mode) to ponder if it was the real Santa. When the Santa returns, he asks if anyone had a jump for his car. Frasier is still amazed and filled with the Christmas spirit because for a brief moment, he actually thought Santa Claus was real.
This happened in a very large number of episodes in The X-Files. Examples include these episodes:
The killer in the episode "Grotesque" is eventually revealed to be a profiler who looked too long into the abyss of a particular serial killer and turned into his copy cat. Whether this is a psychological effect or transferred demonic possession is left up to the viewer.
"One Breath": Who or what was the nurse attending to the critically ill Scully? The supervisor said there was no "Nurse Owens" working at the hospital, and no one matching that decription. We never do get an answer. Was she an angel? A member of the conspiracy planted there? One fanfic proposed she was a friend of Frohike sneaked in so someone trustworthy was watching.
"All Souls": It's left unclear whether Agent Scully's dead daughter Emily was really appearing to her or Scully was hallucinating.
"Irresistible": Donnie Pfaster's shape shifting into demonic forms might have been really happening, or people who saw him were hallucinating from stress and fear.
"Paper Hearts": Perhaps Agent Mulder and serial killer Roche really shared a Psychic Link which allowed Roche to get into Mulder's head. He really read his mind and saw his memories. Perhaps he just found information about Mulder on the Internet and then simply managed to manipulate him.
"The List": It's not clear who was responsible for the murders. Either there was an elaborate conspiracy that bit in the butt all people involved, or the executed prisoner reincarnated and came back, perhaps as a fly.
In "Quagmire," the monster turns out to be just a really big crocodile.
Subverted in "War of the Coprophages." There really are robotic alien cockroaches scuttling around, but they're not responsible for any of the deaths in the episode, all of which are either coincidental or the result of mass hysteria.
"House vs. God": A teenage faith healer somehow manages to shrink the size of a terminal cancer patient's tumor. By the end, it's revealed that the healer had herpes, whose virus has been known to combat cancer. However, as Chase points out, the odds of it being both the right strain of virus and the right type of cancer were astronomical, leaving the possibility of divine intervention open.
In another episode, the team can't identify the problem of a priest who came in with hallucinations of Jesus and got more and more symptoms. He only manages to find the right diagnosis by deliberately ignoring the hallucinations, after which the patient is cured. This leaves the unanswered question of where the visions of Jesus came from if they weren't related to the patient's illness.
In an episode of Eleventh Hour (American), water that cured a boy's cancer proves to be heavy water. However, as the FBI agent points out at the end, this discovery leads to the arrest of domestic terrorists which otherwise would have gone completely unnoticed.
LOST never definitively revealed the show's major mysteries as either essentially supernatural or essentially science fiction. The second-to-last season seemed to come down heavily on the side of science fiction, but the final season introduced plot elements that seemed balanced more toward supernatural explanations. Fans remain divided on whether the show ultimately came down on one side of the question, intentionally left things ambiguous to let each viewer decide, or was attempting a fusion of both SF and the supernatural.
Murdock of the The A-Team is either insane, or a very good actor. Though most of his ramblings (such as that golf balls need to breathe) are clearly not founded in reality, he is actually capable of seemingly becoming invisible to anyone who doesn't know him (either that or he paid off the waitress to play along). Also, at the end of one episode his imaginary dog Billy pulls him off-screen in a manner that couldn't be faked without something else actually pulling him.
An episode of Bones features Booth being helped by his dead war buddy's ghost. In the end, Brennan refuses to accept that it was a ghost, saying it was just a stressed-out hallucination. The later revelation that Booth had a brain tumor at the time may explain it, but the final scene of the episode shows Brennan waving to the "ghost", and at one point, Cam realizes that there was no way for one person to do everything Booth said he did alone.
Another episode was a Blair Witch Project homage. The ghost of the witch is revealed to be fake, until the end, when Angela and Hodgins discover the blurred outline of a woman in some video footage. It could be just moonlight...
Bones in general plays with this trope a lot. Some fans assume it's because David Boreanaz still seems like Angel in the first two seasons, and enjoy making people think that's going to Vamp out to get the bad guy of the week. But it might just be because having one character who is a strong skeptic makes this a very tempting plot device.
The Man In The Morgue takes place in New Orleans, and of course involves Hollywood Voodoo, and even some Easy Amnesia. Surprisingly, it plays the trope rather well - the viewer is left wondering if Bones is drugged or hexed.
In "The Shot In the Dark", Brennan has visions of her dead mother after she is shot in the chest. During her final vision, her mother provides heartfelt advice and then tells her to tell her father, "The first gift he ever gave me, I know he stole it." Brennan refuses to believe that her visions indicate any kind of afterlife, but admits that the advice her mother gave her was sound.
A mild example in "The X in the File" where we get a few alien scares only to turn out to have perfectly normal explanations. One of them even freaks out Brennan when a fossilized woman suddenly rises up during an MRI scan (she had some metal in her). The ending, though, creeps out many viewers using the Nothing Is Scarier trope: Brennan and Booth are only on a car hood in a remove field looking up at stars and discussing the possibility of the existence of alien life. Suddenly, all sounds stop, including the insects and the wind, and the characters look very disconcerted. Smash to Black.
The Castle episode He's Dead, She's Dead has a murdered "psychic" who may have left behind a prediction of her own murder...or maybe it was left by the murderer to confuse the police. Castle wants to believe theory A, Beckett believes theory B. At the end the culprit is lawyered up and not telling.
The episode also had the victim's daughter, also a psychic, tell Beckett that someone with the name Alexander would be important. She finally tells Castle the woman mentioning Alexander to further her argument against psychics since nobody in the case had that name. Turns out, Castle's birth name was Richard Alexander Rogers. She's left to wonder if she was wrong or if it was a coincidence.
"Demons" is set in a supposedly Haunted House, with Castle again taking the role of believer and Beckett the role of skeptic. Although there's ultimately a mundane explanation that plausibly explains the events of the episode, there's still one or two things that suggest the house could be haunted after all.
The physical hints we get of time travel in Time Will Tell can be explained by coincidence. But, and it's doubtful the writer's realized this unless they actually were intending to turn the show int science fiction, what cannot be explained away is that the entire plot makes no sense at all if you assume the 'time travelers' are just delusional. For example, how on earth did Ward get a photograph of the letter? Even ignoring the possibility that the coffee stains are just coincidence, Ward couldn't possibly have taken the photograph, as that letter was written while he was in jail and was in a location he didn't know the address of. And if Ward's real motive was revenge against 'the person who turned in', why does he think that's related to the letter? It is related, but he can't possibly know that without knowing who wrote the letter, and the reason he's doing all the stuff he's doing is that he doesn't know who wrote the letter.
The only way this sequence of events, without time travel, makes sense is that Ward tracked down Deschilde, spied on him, learned that he wrote a letter to Wickfield, broke into Wickfield's house, took a picture of the letter, tracked down Wickfield's half-sister, and then proceeded to torture her to pretend to learn where Wickfield is and then killed Wickfield so he could pretend to learn who and where Deschilde is! Huh?
Doctor Who: The Doctor may have pockets that are bigger on the inside, but he may just cut a hole in his pockets through to the lining. Considering these explanations are given for two different costumes, it may even be both.
The show also featured Satan as a Monster of the Week. Is it really him, or just a Sufficiently Advanced Alien who happens to resemble our popular conception of the Devil and perhaps was even the basis for our and other Devil myths? Never established for certain.
A strange example in the usually reality-based NCIS. In the fourth season finale "Angel of Death", Dr. Jeanne Benoit encounters a little girl outside the hospital who may or may not be the Angel of Death. It's strongly implied to the viewer that she really is.
The Criminal Minds episode "With Friends Like These" features a man named Ben who seems to be haunted by three "demons" who nobody else can see, and who force him to commit murder. The detectives dismiss them first as drug-induced hallucinations and then as symtoms of schizophrenia, but both explanations are eventually ruled out and it’s left unclear as to whether or not they were real.
Criminal Minds makes sweet, sweet monkey love to this trope on a regular basis. Did the Satanic serial killer really have supernatural help, or was he just ludicrously lucky? Did the various psychics that the team encounter really have powers, or was it just a coincidence? Was the bullet that killed Tobias Hankel really divine will, or was it just luck? Rossi gives a little speech at one point where he outright states that he has no idea whether or not the supernatural exists, but that figuring out the answer to that question isn't part of their job, and their job is tough enough as it is.
The Lie to Me episode "Beat The Devil" has the verification of a UFO as its B-plot. Thirty-minute mark, they find (real!) video footage of it. Fifty-minute mark, an Air Force officer shows up, and Loker sees right through him to the truth: The Air Force has no idea what it was, but is more than happy to let the witness twist rather than admit to an unknown penetration of US airspace. They finally get the witness and the Air Force to agree on a story to save the witness' career: uber-uber-top-secret aircraft. Loker smiles and saves the video to hard drive as the episode ends.
In the Boy Meets World Halloween episode "The Witches of Pennbrook", Jack dates a girl who claims to be a witch, and later reveals she has evil intentions: she tries to use Jack as a sacrifice to gain immortality by placing him in the path of a light beam from the sky she claims has destructive powers, though her plans are thwarted by Eric. At the end it is left unclear if she was really a witch or just crazy and if the light beam was real or not. Eric actually says something similar to the trope name when discussing it.
Jack: Eric, I saw the light beam. Was that real?
Eric: Jack, maybe it was and maybe it wasn't. There are some things just too big for our puny heads to comprehend.
The Good Witch, a series of made-for-TV movies on The Hallmark Channel, centers around an attractive woman(Catherine Bell) who relocates to a small town, moves into an abandoned house reputed to be haunted, and opens up a shop full of new-age/occult items, prompting the locals to suspect that she may be a witch. She never does anything overtly supernatural, but it's never confirmed that she isn't a witch either...
In Six Feet Under it was generally clear that the visions of dead people the characters had were in their imaginations (as emphasised by e.g. Nate Sr.'s different behaviour depending on who saw him). Still, there were a few occasions with very slight hints that something more might be going on, as with Claire meeting the dead Lisa, or Brenda meeting Nate Sr. (whom she'd never known while he was alive) or, hardest to otherwise explain, David and Nate sharing the same dream right before Nate dies.
An episode of Cheers involved a guy who wanted to be a priest, who was having cold feet one day before being ordered, who managed to touch an old piano in the bar that has been out of order by years. The piano worked! Cloud Cuckoo Lander Coach even says: “I can’t believe it”. All the cast convinced the guy that it must be a signal that he was special and he must become a priest. He agrees and left the bar. When all comment the miracle, Coach says he repaired the piano a week ago. When they ask him why he said “I can’t believe it” if he knew the piano was working, he answered that all those years he left the piano broke without any further thought, but just a week ago he felt the irrepressible urge to repair the piano, before it was too late.
In Warehouse 13, the basis of the show is powerful artifacts that produce near-magical effects. That's not the trope (although the organization does store them under the theory that someone will figure them out eventually). No, this trope comes into play because most artifacts were owned by famous historical figures well-known for something similar to what the artifact is capable of. It's never made clear whether their extraordinary skills created the artifacts, or if they became famous because they made use of the artifacts.
Artie: Maybe it worked on her, maybe she worked on it...the point is, it worked.
Nanny And The Professor introduced Phoebe, a nanny that arrives in America to tend to a widower and his family—before they even know of her or that she is coming. In the first ten minutes of the show's pilot, Nanny greets an airport's agent, explains where she came from (England) and where she is going. However, the only flight coming from England that day had just arrived at the gate as Nanny walks away. Nanny's ability to speak to animals, her tendencies to know what is coming before it happens, and the like, is never explained. The character of Nanny is ostensibly a Mary Poppins archetype, the magical/mystical housekeeper.
The Christmas Episode of Eureka features Dr Noah Drummer, whose experiment will supposedly bring "peace to Earth," but which actually saves the town and gives it a White Christmas, before he leaves, saying he has "an errand to run", but will be back at the same time next year.
Kid: Sheriff Carter, please tell me you aren't saying this Drummer dude was Santa?
Carter: I'm just telling the story. You can believe whatever you want.
Drummer re-appears in the second Christmas Episode, in which he appears shortly after the holographic storybook that's controlling things has been told to add Santa to the story. As in the previous story, his influence is what gives the story its happy ending. He again refers to having errands to run, and has a dog-sled with a lead dog called Rudy.
The Cold Open of a CSI: Crime Scene Investigation episode showing a psychic giving a reading that makes no sense to her customers, but it apparently turns out that she had foreseen her own death. Or she was a crappy psychic who was just looking around the room for random things to say and the connection of those things to her death were entirely coincidental.
Cold Case does this at the end of almost every episode, often to tear-jerking effect, with the "ghost" of the episode's victim appearing to either the detectives or someone they were close to in life. Normally, this could be written off as simply Rule of Symbolism... except the living people actually seem to react to these apparitions. Notably, the victim in "Disco Inferno" manages to have a fully-choreographed dance number with his old girlfriend from beyond the grave.
An episode of Hetty Wainthropp Investigates had Hetty hired to expose a psychic as a fraud and blackmailer. The psychic predictably uses cold reading techniques to find fodder, and Hetty uses her leading questions to make up a scandalous affair in her husband's past. However, the psychic does accurately describe a long-dead relative of Hetty's when supposedly searching for Hetty's dead husband, and obliquely predicts the birth of Hetty's grandchild, including hints to her name and health complications.
In an episode of Walker, Texas Ranger, a young man steals a priceless jade statue from a Triad gang, believing it has magical powers that can wake his sister from her coma. Walker dismisses this as nonsense, but defends the man from the vengeful gang. The man presents the statue to his sister and nothing happens, but she does wake up when the statue breaks. Walker treats this as a coincidence. It is implied that the statue did have magical powers, as it glowed in the presence of people who could channel their chi like martial artists.
The BBC/Starz series The White Queen portrays Queen Elizabeth (the consort of Edward IV, not the more famous daughter of Henry VIII), her mother, Jacquetta Woodville, and her eldest daughter, also named Elizabeth, as actual witches with real magic powers. Except the show does leave a little ambiguity, since it is possible that all the spells we see them cast appear to work purely by coincidence. For example, when they cast a spell to cause a storm, it is possible that the storm would have occurred naturally anyway. Still, considering that every spell they cast seems to produce its desired result, this would be an amazing series of coincidences.
A particularly interesting example comes from Supernatural Season 2 episode "Houses of the Holy," because the boys have no trouble believing in all kinds of weird and unexplained things, but Dean refuses to believe that angels or God exist. At the end of the episode, even after they've stopped the vengeful spirit from killing the sinful man it was after, Dean watches the man die in a freak accident, and admits the possibility that it was God's will. This becomes especially ironic at the start of Season 4.
In TheWholeTruth, HaroldPerrineau's character is accused of murder because he leads police to a body and claims he knew where it was because he's a psychic. While he does appear to know things which he couldn't have without special powers, evidence is also given that he could have faked it as well. It's left unresolved either way.
In Star Trek: Deep Space Nine, The Federation explains away the Prophets (the divinities of the Bajoran religion) as wormhole-dwelling aliens with a strange relationship to time. The Bajorans reframe the Federation's talk of wormholes and aliens in terms of their traditional religious beliefs. The show demonstrates how each culture comes to different conclusions from similar evidence, without coming down firmly in favour of one interpretation over another.
True Detective, Season 1: Do the birds in the sky actually form a perfect spiral shape, or is Rust hallucinating? Likewise, what about the vortex Rust sees at Carcosa?
The old folk song "Scarlet Ribbons". The narrator overhears his/her young daughter praying for scarlet ribbons for her hair before bedtime. Unfortunately it is very late, and all the shops are closed, making it impossible to obtain them. When the narrator checks on his/her daughter again before dawn, the wished-for ribbons are lying on her bed. The song ends with the lines "If I live to be one hundred / I will never know from where / Came those lovely scarlet ribbons / Scarlet ribbons for her hair."
The Presence, in the Nine Inch NailsYear Zero ARG. In a dystopian future, suddenly a giant glowing blue human arm is periodically seen reaching down from the sky, in locations all over the world. No clear explanation is ever given for what the hell the Presence actually is, but what is known is that it will never appear on video or photographs intentionally taken of it, while those that accidentally capture it can, and that anyone who witnesses it is unnaturally stunned by the sight of it. In-universe theories range from the Presence being God, aliens, or a government weapon, but none of these are ever confirmed before it destroys the world.
"Rosetta Stoned" from Tool. The narrator is clearly having a full-scale breakdown, but the cause is what's open to interpretation. Did he really have a sanity-destroying encounter with aliens who informed him that he had some greater cosmic purpose, or did he just have a really bad trip? Given Maynard's attitude towards giving a straight answer about a song's meaning, either interpretation could be correct.
In Alfred Noyes's "Forty Singing Seamen", it concludes with the narrator's observation that might all be Pink Elephants. To be sure, that included drinking the grog.
Across the seas of Wonderland to London-town we blundered, Forty singing seamen as was puzzled for to know If the visions that we saw was caused by—here again we pondered— A tipple in a vision forty thousand years ago. Could the grog we dreamt we swallowed Make us dream of all that followed? We were only simple seamen, so of course we didn't know! Chorus—We were simple singing seamen, so of course we could not know
Warhammer 40,000 loves this trope as a cornerstone of its setting, especially when the Adeptus Mechanicus come into play. Is that ancient relic so powerful because it was created with long-lost technology of astounding power, or is it truly blessed by the Emperor to protect his children? Do the Necrons invoke some strange techno-sorcery in their weapons and vehicles, or is their understanding of the material world so absolute that we can't even begin to understand how they work? Are the Legion of the Damned mystical undead, or just regular marines suffering from some ungodly mixture of the Black Rage and Nurgle Rot? The answer is very, very rarely made clear in any given case. This is made worse because it has to be on a case-by-case basis since magic and super-tech both exist in the setting, and some tech (especially that used by Orks) is explicitly a mix of real mechanical systems and Clap Your Hands If You Believe.
Mage: The Ascension had some fun with this too. Any smart mage makes their spells look like coincidences, hypertech, or something else that the general population believes will work (and a fair number actually believe that this is what is happening). With the heavy levels of Clap Your Hands If You Believe used, the odds are very good that there's a bit of both magic and coincidence/super-science/whatever going on.
The really mind-bending part is that the universe is designed to behave, mechanically, the way the mage thinks it behaves (the 'paradigm' mechanic), so a scientific test devised to determine whether something is one or the other will always empirically show that it's "magical" (whatever that means to the mage's paradigm) so long as it's the mage performing the test. Technology that appears to be "non-magical" isn't actually mundane, it's part of The Lie that the Technocracy has spread to suppress direct will-work.
The New World of Darkness sourcebook Asylum presents a suite of odd happenings and disturbed individuals in the ill-starred Bishopsgate Mental Hospital in one chapter. The book gives each of them one or more supernatural explanations... and also gives a mundane one for each, with the "real" answer in the Storyteller's hands. (For example, one of the patients is a woman with foggy memories and terribly-kept medical records. The book gives two possibilities: she's being used as a storage conduit by the Seers of the Throne, who alter her records to hide their activities... or she's just an ill woman with an aneurysm on the verge of bursting, and the hospital's just really screwed up keeping their books straight.)
Dungeons & Dragons 3.5 edition had a prestige class that pretended to be a spellcaster, using prestidigitation and really good bluff skills. Ironically, Prestidigitation is also a spell available to wizards, sorcerers, and bards, which enables them to perform minor tricks such as slow levitation of small objects, limited control of temperature, clean or soiling objects, or create crude objects from nothing.
Pathfinder ups the ante on this a bit by giving rogues (the "tricky" non-magical class) access to actual spells as class "tricks". Because they're so good at faking it, sometimes even the universe just gives up and believes them.
BattleTech's "Phantom 'Mech" ability, which was displayed in the BattleTech Expanded Universe. In combat, Morgan Kell's and Yorinaga Kurita's battlemechs became completely invisible to sensors, and targeting systems were completely unable to detect them. Attempting to fire upon them resulted in the weapon missing entirely. It's never explained what exactly it is; whether it be destiny, or a LosTech stealth system.
The Fate systems such as Dresden RPG and Strands of Fate have the Aspect system where all characters have a set of "Aspects" which basically causes PCs and other important characters to have a serious case of Plot Happens in their general vicinity. Leaving you to wonder in some settings whether there is something special about these people.
The Winter's Tale by William Shakespeare: At the end, Queen Hermione's statue seems to come to life. It could be that the statue of Hermione really does come to life, or it could be that her servant, Paulina, kept her hidden for years and she only claimed she had died.
Next To Normal: In the end, although the family does begin to heal and move on, it's left a bit unclear whether Gabriel was just a hallucination or actually was a ghost desperately holding onto Diane to keep "living". The reprise of "I Am the One" could easily support either conclusion.
In The Phantom of the Opera, it's deliberately left ambiguous as to whether the Phantom actually does have supernatural abilities. Some of the things he does, like the mirror, are understandable, but a lot more - causing the piano to play itself during the rehearsal of Don Juan Triumphant, creating fire in the graveyard, making the gates in his lair rise with merely a gesture, disappearing from under his cloak at the end of the show - while obviously stage effects in real life, have no practical explanation in the context of the story. However, the film version makes it very clear that all the stunts he pulls are merely clever tricks, leaving the more supernatural stuff out altogether and explaining other things away by showing the Phantom pulling a lever to raise the gates, or messing with Carlotta's throat spray in order to make her croak.
Scratches. The entire point of the plot is this: you are constantly bombarded with a mix of "magic" and "mundane" arguments up until the very end, and it's still not entirely clear which one was at work. Was there ever a curse on the mansion, or was it all just the result of a series of terrifying misunderstandings? Made even scarier when you consider that the mundane explanation behind the mystery is, arguably, at least as terrifying as the supernatural one.
Metal Gear Solid 2. Among many, many other examples, there is Fortune. Is she Immune to Bullets due to luck-based powers, or a prototype force field? If it's the force field, then why can she deflect missiles after the force field has been proven to be deactivated? Also, she managed to survive a gunshot wound due to her being one of a very few number of people with their hearts on the opposite side of their chests...
Dragon Age uses a variant on this trope with Andraste, the backstory's expy of Joan of Arc and Jesus. The church's doctrine is that she genuinely enjoyed the favor of the otherwise absent Maker and through her, the Maker wrought miracles - and that Andraste's ashes in Origins have genuine miraculous power. It's suggested, however, by non-church characters, that Andraste may simply have been a powerful sorceress who fooled the world and that her ashes have power as a result of being stored near a massive deposit of incredibly pure lyrium. As with all things related to the Chantry's doctrine in-game, the writers leave the truth intentionally ambiguous.
A variation in Dragon Age II why there are constant problems in Kirkwall? Is it because the city's layout was set down to create powerful sigils for some unknown magical purporse? Something the Tevinter Mages did when they controlled the City or some curse bestowed when they lost it during the slave uprising? Is it because the Veil between the Fade is particularly weak there? Maybe its proximity to the Primeval Thaig and vast amounts of Red Lyrium that drive people crazy? Maybe its proximity to the Ancient Darkspawn Corpypheus slumbering in his Grey Warden Prison? Or maybe its because the people who live there just make it a Crapsack World?
Just what the hell is up with Sandal and why does he keep being found surrounded by countless dead Darkspawn, Demons, etc?
Hawke: I'd really like to know how you killed all those darkspawn?! Sandal: *Hands them a Runestone* Boom! Hawke: And how did you do that?! *Gestures to a Ogre frozen-solid and in mid-charge* Sandal: Not Enchantment!
There are a number of fan theories surrounding Sandal. Dwarf who has somehow learned to use magic? note But that's impossible, Dwarves cannot use magic in any wayOld God manifested in the form of a Dwarven boy? note Remember, he was found in the Deep Roads, miraculously unharmed And what's with this weird line he spouts in Dragon Age II?
The Half-Life 2 mod Black Snow plays with this trope a lot. It's revealed the eponymous black snow is a heavily parasitic and aggressive form of spore-based fungus that is immune to most environmental hazards but regular light and above, but that doesn't explain the strange whispering and noises it emits, the ghastly groan it makes when it attacks, the mysterious presence of a Slenderman-like figure in drawings made by the research staff who shows up on a laptop's wallpaper while you're searching it for files and in a sensory deprivation chamber's induced hallucination, the bizarre fossil core that it seems to emanate from when it was dug up, that it seems to be actively screwing with the player character's camera in the ending by plastering what appears to be the faces of the researchers of the center it attacked and images of a cave...
Takane Shijou of The iDOLM@STER is implied to be from either the Moon... or Germany.
Pretty much every entry in the Silent Hill franchise plays this trope. In each one, it's intentionally unknown if all of the monsters, characters, Otherworld transformations, weapon/item placements, and strange scenery pieces that Harry/James/Heather/Henry/Travis/Alex/Murphy encounter are either legitimately happening and being fought with, or are all merely drug-induced halleucinations or bad nightmares; the first game alone demonstrates as much evidence of the cult's White Claudia drug smuggling operations as there is talk of the town's still-mysterious past, Alessa's "strange powers", and the cult's creepy rituals. One of the endings for that game even suggests it was all a dying dream, but is considered non-canon. Perhaps most bizarre of all, however, is that a cutscene towards the end of Silent Hill 3 has Vincent remarking "They looked like monsters to you?", suggesting both the hallucinations-possibility again...and that our protagonists may actually be killing innocent people or cult members instead! Of course, he says he was joking afterwards, but nobody knows even to this day...
Also from Silent Hill 3 is the true nature of Leonard Wolf. When Heather encounters him, he appears as a large, aquatic beast. Despite this, Leonard's daughter is completely human, and no character ever mentions anything unusual about Leonard's appearance. It is possible that Heather was instead seeing Through the Eyes of Madness?
The Dunwich Building in Fallout 3. There's a lot of fucked-up stuff that goes on in there that can be rationalized as, say, hallucinogenic gases, or maybe an odd variant of radiation, but that explanation still doesn't cover everything. It's entirely possible that the Dunwich Building is perfectly normal- well, as far as 'normal' goes in Fallout. But it's also entirely possible something dark and eldritch lurks there. We'll never know for sure.
This goes even further and yet also stays precisely the same in a mission in the expansion pack. You're asked by a somewhat creepy old man to retrieve a book - supposedly, a tome of eldritch lore. You're asked by an old Christian missionary to destroy it by pressing it against the monolith in the basement of the Dunwich Building, which will destroy the book. It's entirely possible the book is made out of some strange radioactive substance that reacts poorly to whatever the monolith is made of - or it might actually have genuine arcane power.
The Point Lookout DLC had some Dummied Out plot points regarding the book according to The Other Wiki. Apparently Obadiah Blackhall was specifically asking for the help of the Christian Missionary to help him destroy the book, when she receives the notification of this she proclaims that Obadiah is a good man but comes from a bad family. When the book is brought to him Obadiah was supposed to tell you that the book was used by his family for occult purposes in ancient times and that it has demonic origins, he explains that there are two ways to destroy the evil magic contained in the book; either sacrifice himself or destroy the book in the Dunwich Building. This cut content makes it far more explicit that the book is magic.
In Fallout 2, there is a town wherein you can meet a translucent woman who claims to be a ghost, but in dialogue you simply ask her to turn off her Stealth Boy, an item from the first game which, well made the user translucent and thus harder to see (hence the name). So is this just a mentally disturbed woman with Stealth Boy, or an actual ghost?
Fallout: New Vegas shows that prolonged usage of Stealth Boys among Nightkin has made them schizophrenic, giving evidence to the former. However the effect has never been observed among humans…
In Michigan: Report From Hell, it is heavily implied that the monsters in the game are a result of experiments, with plenty of evidence to back it up, however, at the same time, you can find strange things, such as bed-sheets floating as if someone is laying down in them, an oven being on even though the place is abandoned (though whether or not it was left on recently is another unanswered question), and a few other things, these possibly implying that there are unnatural forces at work.
Sherlock Holmes: The Awakened: The various Cthulhu related elements are treated this way. It could be the Great God himself causing storms and the end of days, or simply a very large number of crazy people. The best example is when Sherlock uses an incantation said to exorcise demons to subdue a gunman. It may have worked, or it might have just his own beliefs working against him.
Pokémon Red and Blue: Did that girl in Lavender Town really see a white hand or was she just teasing?
Bully has various clues, hints, sightings, and sounds that there is a werewolf loose in town, leading to lots of online controversy in the gaming world, making some gamers wonder who that werewolf is, and making other gamers claim that there is no werewolf at all.
Far Cry 3 has this all over it. So many things on the island, like the animal's ultra-aggressive, almost Hive Mind-like behaviour, Jason's prophetic hallucinations, the alleged "demon" Jason fights about halfway through the game, an NPC who is heavily implied at the end to have been a ghost, the way the local natives seem to be slowly going mad, old letters from WW2 Japanese soldiers reporting crazy shit going on... The list just goes on, and the worst thing is, in true trope form, we're just left to wonder if it's all real, or the protagonist simply going insane. And there's plenty of evidence for both. It's border-line terrifying.
In Attack Of The Friday Monsters A Tokyo Tale, while some of the strange goings-on are given definite natural explanations (the monsters that had been appearing are just stagecraft made by the local TV station), other aspects of the plot tend to be more ambiguous about whether they're real events or fantasies of the game's child characters, particularly as the adults act like it's all real while the kids are around. And some of the stranger happenings don't get any naturalistic explanations at all (such as Sohta's abduction by the UFO and transportation to the diner.
Similarly to the Medieval II: Total War example, a number of events in the Crusader Kings games are seen by the characters as explicitly supernatural or miraculous, but could have more plausible explanations. To give but one possibility: Is your king genuinely suffering from Demonic Possession, or are the voices in his head simply the result of a mental disorder medieval medicine knows nothing about?
In the first section of Mass Effect 3, Shepard runs across a young boy in a half-ruined building, has a few lines of conversation with him, and then has to leave. Later, the same boy is spotted climbing into a shuttle which is promptly shot down. End of story? Maybe... but between his seemingly impossible Stealth Hi/Bye (Shepard turns away for a few seconds, and he climbs out of sight — in an air vent), his vague, panicky dialogue that is totally correct, the fact that no one else seems to see him or ever interacts with him — not Anderson, not anyone on the shuttle he's climbing aboard — and not least the Catalyst at the end of the game coincidentally (?) basing its avatar on him, well, things seem a little fishy. Naturally, fan theories hopped the first train out of Rational Town and never looked back. Well, theories of indoctrination are technically mundane in this sci-fi setting...
A more obvious example is the Citadel DLC's culmination to Thane Krios' Romance Sidequest: is the ghost of him that Shepard sees an actual spirit of the dead, or her going mad from stress?
When Wardog pull a Let's Get Dangerous moment mid way through Ace Combat 5: The Unsung War the enemy freaks and believe the Demons of Razgriz (a mythical tale part of the game revolves around) took over the pilot's bodies. The squadron runs with the idea later on and renames themselves Razgriz, but whether or not the myth is true is left up in the air.
In Red Dead Redemption, a side quest has Marston meeting up with a mysterious stranger who seems to know an awful lot about him while also remaining impervious to bullets. Is this man some sort of supernatural entity? Is he all in Marston's mind? The game isn't really clear on that one.
The entire premise of Umineko: When They Cry is based on this, so much that the creators have established two distinct camps where the fans can take sides. There's Fantasy, for those who favor the idea that everything was done by witches and magic, and Mystery, which believes that everything was done by human hands, and that witches were no way involved. This becomes increasingly difficult, as more than a few Epileptic Trees are bound to pop up in order to explain everything done by human means. Now, that's the simple part, but with Anti-Mystery and Anti-Fantasy mixed in, everything gets a whole lot weirder. While it's never outright stated whether everything is magic or mundane, there are hints in the second half of the series that make it lean more towards the mundane side. This includes the fact that three characters are actually the same person, and how it's implied that this person created many of the magical beings as Imaginary Friends. There's also the fact that, while Beatrice spent the first half of the series trying to get Battler to submit to her and be convinced that the murders were done by magic, EP5 reveals that she doesn't want to win at all, but to make Battler win.
Higurashi does this too; the "Wrap Party" at the end of the first novel has all the characters arguing about whether the events were due to humans or a curse. Amusingly, Ooishi takes the side opposite what he does in the novel, and Keiichi doesn't care, since they're all trying to get him anyway. However, it's resolved eventually: It's mostly mundane, with the weirdness being a combination of a Government Conspiracy and Hate Plague; however, the repeated arcs are due to magic, and Rika remembers all of them. In other words, there is "magic" at work, but the murder mystery is 100% mundane and magic is only used to "explore" it.
Hatoful Boyfriend has Anghel, who is always off in his own bizarre fantasy world and claims to be the reincarnation of a fallen angel. Time spent around others tends to draw them into it and they speak in the same overwrought, Purple Prose-y way he does, about gods and demons and fantastic things. The end of his route in the first game involves confronting the Obviously Evil Shuu, who there refers to himself as Dark Sorcerer Wallenstein and summons Himnesia, Bringer of Death. When Himnesia is defeated Shuu retreats and is never seen at the school again. Bad Boys' Love has a report saying that he secretes hallucinatory pheromones, which he's not immune to, and acts as a neurotransmitter, so he's kind of sucking other characters into his own constant trips... This is an odd sort of mundane, but it seems semi-plausible. Except that Anghel often knows things he should have no way of knowing about - the weird names he uses for people, if translated, often tie in to secrets they hold, and he seems to have a sense for diseases.
In Holiday Star a villain draws blood from him and uses it to take the power of otaku fantasies and convert it into a from which powers a Death Ray - and the ray is countered by Anghel and some others taking on a fantasy that they are Magical Girls and using their magic powers to shield. He may be a Reality Warper.
Fans! is certainly not "mundane" in all respects, but in a sequence where Guth visits his cousin in the afterlife, one of the first things he does is explain why it can't be a dream (arguing that it's a Lotus-Eater Machine), but when he wakes up in his chair, he promptly takes it as one rather than accept the idea of life after death.
Parodied at the end of Avatar episode of Monster of the Week. Mulder and Scully argue about old lady that was haunting Skinner in this episode:
Mulder:I think she was the ghosts of Vietnam.
Scully:I think she was Mulder's mum.
Peter, the enemy of the Affably Evil title character in Niels, is regularly visited by and engages in not-always-consensual-on-Peter's-part relations with a demon only he can see. No proof as of yet whether it's real or a product of all the drugs Peter's on.
Mary/Christina from The Adventures of Dr. McNinja had the ability to perform spells at random to help save the world, but every one of her miracle spells left open the possibility that they had happened by chance.
Word of God is that Dissonance will go this route—there will be a "scientific" interpretation and a "religious" interpretation, and both will be equally valid.
While the existence of magic is an established part of the setting in El Goonish Shive, the existence of the divine is kept far more ambiguous. In particular, a certain type of spell, known as a "guardian form" is speculated in-universe to be divine in origin. On the one hand, Nanase was praying at the moment she acquired hers, and it does turn her into an angel, making the possibility of divine intervention sound more likely. On the other, it was well within the established rules of the setting for her to gain that spell at that moment, so it may have just been perfectly ordinary magic.
In The Order of the Stick, the deceased Lord Shojo appears to Belkar when the halfling falls into a coma, as a result of triggering his Mark of Justice. Shojo says he could be either the real deal's spirit, appearing to Belkar from beyond the grave, a personification of the Mark of Justice (which makes sense since when it was first activated it also produced an image of Shojo), or simply a fever-induced hallucination.
The Toughs from Schlock Mercenary get the deal they do on the PDCL due to strange voices convincing Petey the ship is haunted, driving him insane. Fixing the ship's plumbing fixes the issue, but due to the specificity of the utterances, Petey finds this explanation so untenable that only enforced cognitive dissonance can keep him from committing suicide.
Succinctly summarized by the God-entity in Futurama (who is in himself an example - the most description given was that being "the remains of a space probe that collided with God" "seems probable"):
"When you do things right, people won't be sure you've done anything at all."
King of the Hill: Did the TV remote that helped Peggy change the channel to convince Hank to be on Luane's Manger Babies show, contain batteries, or didn't it?
Lisa: I didn't turn it on, I thought you turned it on.
Homer: Oh, well, turn it off anyway.
Lisa: (mysteriously) It is off.
In the South Park episode "Cartman's Incredible Gift" the police believe Cartman is a psychic. Kyle points out at the end that no one is psychic and there is a logical explanation for everything that is supposedly supernatural. However, when Cartman and a group of other psychics engage in a psychic battle, with a lot of wild hand gestures and odd vocalizations, Kyle gets extremely fed up and screams at them to stop. As he yells, the lightbulbs shatter and the shelf above his bed breaks. After a beat, Kyle says there is a logical explanation for that, too.
Mr. Hanky the Christmas Poo is this. He initially looks like an ordinary piece of poo to most people, which gets the boys in a lot of trouble at first, but he moves and talks to the boys in private. The ending confirmed him as definitely magic when he showed up in front of everyone for a speech.
Is Mr. Hat a living and sentient being or is he just a mere hand puppet?
The end of every episode of Mona the Vampire would end with both a logical explanation for what happened, but also hinting that something magical did occur. For example, an episode where a T-Rex came to life ended with Mona revealing a fresh dinosaur footprint in the soil.
Very common in the episodes of Hey Arnold! where the kids investigate the city's urban legends; usually, the episode will end with them discovering what seems to be a logical explanation for the myth (for example, the mysterious train that supposedly delivers people to the Underworld was actually just going to a steel mill), only for... something... to happen in the last few seconds, visible only to the viewer and not to any characters in-universe, that casts doubt on a purely mundane interpretation.
The ending of the My Little Pony: Friendship Is Magic episode Hearth's Warming Eve features creatures known as Windigos—horses that spread ice and wind and snow wherever there's hatred. At the very end, the Mane Six get in a brief argument while a snowstorm rages on outside. They stop upon hearing the sound of wind, which is eerily similar to the sound of the Windigos...
A few episodes in Avatar: The Last Airbender end this way, particularly The Fortune Teller and The Swamp. Avatar uses basically every combination of mundane or magical explanation at some point.
An episode of Batman: The Animated Series dealt with this trope. If you'd only watched the cartoon, they make it clear, even to the point of explanation, that Zatanna's tricks are just stage magic. If you read the comics however, you know that Zatanna is capable of magic, and it's later confirmed on Justice League. So the question is, was any of it real, or did she just play it straight throughout the whole episode?
The episode Read my lips has Batman analyzing the Ventriloquist and Scarface's voices in the Batcomputer. The result shows that those voices belong to two different persons. Batman also says to Alfred that he studied with the world greatest ventriloquist, Zattara (Zattana's father) and that the Ventriloquist could give him lessons. So, In-Universe, they aren't sure if the Ventriloquist is just way better artist that the world greatest magician, or if Scarface is truly a Demonic Dummy.
In The New Batman Adventures, Scarecrow went through a major design overhaul because the crew felt that he didn't look scary enough. The redesign is far more undead, featuring the character looking more like a priest in a wide-brimmed hat with a noose around his neck, long hair, and the face looks along the lines of a skeleton. The creators indicated that they weren't even sure if the character was human anymore, and whether or not it's just a costume.
Used in Young Justice with Holling Longshadow. When talking with Jaime about his grandson Tye's disappearance, he gives Jaime some advice that sounds like nonsense at first. As the show unfolds, however, it turns out to be Foreshadowing. Here's the conversation, with the double meanings in asterisks.
Longshadow: He won't be back for a few weeksnote he is eventually returned safe and sound a few weeks later. He's begun a quest of awakeningnote his metagene gets activated by the Reach that will link him to his heritage note the gene and show him the path to his destiny note he gets superpowers. Maurice is just a distraction note Tye's mother's boyfriend, hinted to be abusive towards Tye, and who Jaime thinks is responsible. He has nothing to do with it. He plays no part in Tye's vision quest, or in yours.
Longshadow: You search for answers, but the answers you seek will find you note Impulse arrives the next episode looking for Blue Beetle in order to tell him about the Scarab. Only then will you make peace with the one inside you note the Scarab, the A.I. in Jaime's spine he has trouble controlling.
Used in the Halloween episode of Doug, as well as a few other episodes (like the one with the "lucky cap"). Doug and Skeeter are helped by a mysterious cloaked figure who later claims to be "Baron Von Hecklehonker", a character in the framing story about Bloodstone Manor, right before disappearing into thin air.
Plank from Ed, Edd n Eddy is either a board with a face drawn on it that Johnny goes through extreme lengths to support his imaginary friend, or an actual separate entity that really can talk only to Johnny.
In the All Grown Up! episode "It's Cupid, Stupid" it was left ambiguous whether Lil' Q was really Cupid or it was just a coincidence that people were falling in love after getting hit by his hacky sack. The last person to be hit by the hacky sack, right at the end, didn't seem affected by it.
Distraught over seeing his paramour Betty/Sara Northrup fall for his friend L. Ron Hubbard (yes, thatL. Ron Hubbard), rocket engineer and occultist Jack Parsons conducted extensive magickal rituals to summon or conjure an elemental mate to replace Betty. After performing the final ritual in the Mojave Desert, he returned home and immediately met Marjorie Cameron, his future wife.
Similarly, when Betty and L. Ron played a confidence trick on Jack, using almost all his money buying several yachts and going on a cruise under the pretense of a "business venture," Parsons realized what they were doing and performed another ritual to stop them. Not long after, Hubbard's ship was struck by a squall, forcing him to return to port and face Parsons' wrath.