Perhaps among the scariest beings to ever be imagined in human culture, ghosts are no joking matter when it comes to dispensing Nightmare Fuel. There's a reason they're a common element of horror movies.
There are three types of the Ghastly Ghost:
1) Some are primarily just plain not pleasant to look at, with grotesque, unnatural facial and body appearances. Alternately, they might still look quite human but their ghostly state reflects the exceptionally gruesome and violent way by which they died. Even worse, they may not look like this all the time, meaning that the people they interact with are unaware that the Cute Ghost Girl interacting with them has a horrifying actual appearance. On the plus side this type includes Dark Is Not Evil or Non-Malicious Monster, when only the appearance is unsettling and it's actually a Friendly Ghost. On the bad side just look at type 3.
2) Some of them are malevolent and can actually harm anyone that do get too close- or spirits forbid, it's a Vengeful Ghost with a goal of inflicting general mayhem to avenge a (real or perceived) wrongdoing done unto it. Type 2 Ghastly Ghosts invoke Beauty Is Bad or Face of an Angel, Mind of a Demon, when it's particularly pleasant to look at but is all but pleasant in actions.
3) A combination of the two aforementioned types; they're both horrifying in appearance and malevolent in deed. This type of ghost can be a Knight of Cerebus that turns any work much darker than it normally is, if it isn't the main subject of the work to begin with.
Poltergeists are typically this, though they run the gamut from mildly annoying to terrifying. A Stringy-Haired Ghost Girl is this most of the time, particularly if we do not know what she looks like under the face-covering hair. If the ghost is only nightmarish when it wants to be, that's Game Face. Murder Into Malevolence is when a murder victim turns into this, or Madden Into Misanthropy if it goes badly enough. This ghost regardless of type will taint their home area, sometimes turning it into Unholy Ground. Or worse, they do it to people.
The Headless Horseman is usually a variant of this, a malicious ghost (or otherwise undead being) who either scares people or even kills them by beheading. Ghost Pirates are also often villainous, haunting the sea and attacking sailors.
- Fantasia: The "Night on Bald Mountain" segment plays this trope completely straight. You have hordes of spirits that ride skeleton steeds and some flying shrouds with glowing eyes on the inside.
- Final Fantasy: The Spirits Within: The Phantoms, noncorpreal alien beings that can rip out the souls of humans and have killed off most of humanity, are revealed later in the film to actually be ghosts of alien warriors that were killed when their homeworld was destroyed during a civil war. Their assumed "ship" is little more than a piece of their destroyed planet, and their actions are purely driven by their confusion, rage, and lunacy.
- In Casper, Casper's three uncles Stretch, Fatso, and Stinky are mainly just pranksters, but they also try to kill Dr. Harvey.
- Ghostbusters: Ghosts are typically very destructive, and can vary from simply malevolent spirits to monstrous and aggressive entities to borderline Eldritch Abominations, depending on their individual power and origin. A given ghost's rampage may be limited to annoying pranks, or it may involve violent mayhem or the very real threat of a localized apocalypse.
- The Lord of the Rings: The Return of the King portrays the Army of the Dead as a horde of green, intangible ghosts whose faces look like living corpses. They are first hostile, but Aragorn shows them the sword that proves he's the heir to the throne of Gondor and promises to release them once they fulfilled their oath by joining him for the Battle of Pelennor Fields.
- A Nightmare on Elm Street: The main antagonist of the series is Freddy Krueger, a burnt-skinned ghost who invades people's dreams to kill them in their sleep in a terrifying fashion. He was a Serial Killer of children in life, and continues to spread fear and death as a spirit.
- Raiders of the Lost Ark: When the Ark of the Covenant is opened, Indy warns Marion and the audience not to look just before spirits come out of the Ark. Indeed, no sooner has Belloq said "It's beautiful!" than the spirits reveal they're anything BUT.
- Harry Potter:
- The Bloody Baron fits this trope aesthetically, being a howling, chain-rattling, sword-swinging ghost. Most ghosts in the series, however, fall into the Friendly Ghost category, with Peeves being the most malicious, and he's more of a peeve than an actual threat.
- This trope is downplayed for Nearly-Headless Nick, who is friendly and doesn't usually look gruesome, but he is partially-decapitated (which was how he died) and can almost remove his own head, which grosses out some students.
- Princesses of the Pizza Parlor:
- Grandmothers and Other Fearsome Encounters:
- Ghost dancers consist of a gentleman with only half a head upon his shoulders, or some young lady whose throat was graced with a necklace of her own blood.
- A Scary Librarian ghost has mind-affecting magic based on the literacy of the target to enforce silence, whose writing is in Zalgo text, and is uses her own eye sockets as inkwells.
- Banquets and Other Social Disasters: An "enraged phantom"'s head is a bare skull with a fringe of hair like fire around the edges and empty eye sockets.
- Grandmothers and Other Fearsome Encounters:
- Scary Stories to Tell in the Dark
- The haunt in "The Haunted House", despite being a benevolent entity who just wants her killer brought to justice, is portrayed in the illustration with an absolutely horrific Nightmare Face, with empty rotting eye sockets, no nose, and a lipless mouth that weakly hangs open. This illustration is the most infamous in the series for a reason.
- There's also "Thup-p-p-p-p-p!", one of the "funny" stories, which features a young girl who is stalked by an eyeless ghost that appears in her room and disappears whenever her parents appear. The story ends with the ghost simply Blowing a Raspberry at the girl, but the illustration still falls into Surreal Horror territory, depicting the ghost as a bizarre creature almost resembling melting wax.
- In Aidan Chambers' short story "Dead Trouble", the ghost protagonist is trying to contact someone in the living world to let them know where his body is buried. At one point he tries to manifest himself to his former workmate as a faintly glowing figure, but in his haste he botches it and appears as a distorted monster surrounded by a hideous corpse-light. His colleague, and his colleague's date, unsurprisingly flee in terror.
- House of Anubis: Senkhara is an evil ghost woman who stalks, torments, and curses Nina and her friends. Due to being intangible, Nina and her friends can't do anything to hurt her, and being made of what looks like black smoke contrasts her with the far friendlier ghost of Sarah Frobisher-Smythe. Her introduction ramps up the stakes and the dark tone of the series, and every character who met her — student or adult — is terrified of her from the get-go.
- In Japanese folklore, Onryo (which, for bonus points, means "Vengeful Ghost" in Japanese), are a definite case of Type 2: they are ghosts of people who died with such strong passions- jealousy or anger, typically- that their soul, unable to pass on, turns into a wrathful, vengeful spirit hellbent on inflicting as much harm as possible. They are powerful enough to kill any person swiftly, but rarely do so, preferring to let their target suffer as long as possible. Their taint on a person or place is contagious and indiscriminate, and the taint itself lasts long after the ghost itself is laid to rest (if it was ever). For these reasons, they're this trope to Japanese people, being The Dreaded of all supernatural beings.
- In Jewish folklore a dybbuk is the malicious spirit of a deceased human with a tendency to possess the living. The dybbuk box is the subject of many urban legends that suggest it to be a real life instance of Sealed Evil in a Can.
- Dungeons & Dragons:
- In early editions of the Advanced version, ghosts are Lawful Evil undead who are so terrifying that they cause their victims to suffer Rapid Aging: ten years just for seeing them, ten to forty by being touched by them.
- Wraiths are incorporeal undead born from hatred and darkness, and deeply despise all living things. Their touch alone is enough to drain the life from their victims, and all creatures they slay rise as new wraiths enslaved to their killer's will.
- 5th edition gives ghosts the Horrifying Visage ability, which terrifies anyone looking at it (and if they're particularly badly frightened, ages 10-40 years). They can also possess people (who remain aware of everything happening to them). Both these abilities can only work once a day on the target, but the Rapid Aging can only be cancelled within 24 hours as well.
- Games Workshop games:
- Warhammer: Ghostsnote and Spirit Hostsnote are malevolent spirits summoned and bound by necromantic energies. These tortured ethereal undead creatures typically have a hideous, semi-transparent form that can cause all but the bravest of mortals to be paralysed with fear. On the tabletop, Ghosts and Spirit Hosts have the Fear special rule that makes it more difficult for enemies to attack them as they cower from the horrific spirits.
- Warhammer: Age of Sigmar: The lesser Malignants known as Spirit Hosts are the souls of damned that have been stripped of their identity and merged into a cloud of ethereal energy. These spectral creatures often accompany Legion of Nagash and Nighthaunt armies in their campaigns across the Mortal Realms, frightening the life from the mortals that they encounter.
- Wraiths are, much like in D&D, light-hating specters closely connected to the deadly powers of the Negative Energy Plane, and are born from the souls of murderers. They remember little of their lives beyond a powerful sense of hatred and anger, and consequently despise all living things. They victims are raised as more wraiths under their murderer's control, becoming free-willed but no less hateful should their master be destroyed.
- Spectres arise from murder victims, their souls given unlife by their rage at their fate. They hate all living things, haunting the sites of their deaths and killing anyone who comes close. Like wraiths, they are repulsed by light and raise their victims as more of their kind.
- Geists are spectral undead created when a humanoid is killed by a haunt — a non-creature manifestation of the negative emotions created by a great tragedy or loss of life — and remains shackled to the material plane by its bitterness and anger. They can control existing haunts, and emit horrific laughter capable of sending living creatures into a mindless panic.
- Dybbuks are the souls of criminals, sinners or suicides who remain in the world of the living to stave off the judgement that awaits them. They take out their dread and anger at their inevitable doom on the living, spreading death and mayhem wherever they go.
- The Haunted Mansion: While many of the ghosts can be frightening to look at, a few stand out as particularly terrifying:
- Unlike the other playful ghosts of the mansion, Constance Hatchaway is an Axe-Crazy ghostly bride with an obsession with removing her husbands' heads with her hatchet.
- The Hatbox Ghost has an "evil, grinning face" and a head that disappears from his shoulders and reappears in his hatbox, and he cackles as people pass by him. In the comics, he is actually responsible for murdering the Ghost Host's bride on her wedding night just to spite her groom.
- The Ghost Host is an omnipresent spirit in the mansion who laughs and makes creepy threats as he follows people throughout. He revels in being a scary spirit, showing off a painting of him decaying and his hanging corpse in the rafters.
- Disneyland Paris has the Phantom Manor and its titular Phantom, the local version of the Ghost Host. He's heavily implied to be the father of this ride's version of the Ghost Bride who was very possessive of her in life and murdered her fiancee on their wedding day, tricking her into thinking he left her at the altar.
- Donkey Kong Country 2: Diddy's Kong Quest:
- The Kloak enemies are ghostly waistcoats who cackle and throw basic objects at Diddy and Dixie.
- In "Haunted Hall", Diddy and Dixie are riding a roller coaster through a giant library inhabited by a ghostly crocodile pirate named Kackle, who chases them down. As Kackle chases them, a time limit appears at the top of the screen. If time runs out, then Kackle catches Diddy and Dixie, costing them a life, and cackling as he does so. Collecting Green + Barrels adds more time to the time limit, but collecting Red - Barrels takes time away.
- The boss of Gloomy Gulch is Kreepy Krow, the ghost of Krow, a giant Mini-Necky who served as the game's first boss. Kreepy Krow is trying to kill Diddy and Dixie as revenge for killing him, and he summons ghostly Mini-Neckies to attack them. By killing the living Mini-Necky, a barrel appears, which Diddy and Dixie can use to attack Kreepy Krow with.
- Fate/Grand Order: Ghosts appear as enemies that are represented as skeletons that lack legs and a pelvis in favor of an extended spine, and have enlarged hands to give the impression of huge claws. The King Mook variant has extra arms and the skulls and rib cages of multiple humans stuck in its torso.
- In Moshi Monsters, the mission "Monsters vs. Ghosts" features some evil ghosts who trap Tamara and the ghost of the main villain Dr. Strangeglove's missing hand.
- Pac-Man: Blinky, Pinky, Inky and Clyde are a quartet of ghosts who serve as the main enemies of the games. They spend their time chasing Pac-Man around the maze, trying to prevent him from eating all the Pac-Dots that send him to the next level. If they touch Pac-Man, he loses a life. When Pac-Man finds a Power Pellet, it temporarily turns the Ghosts blue, allowing him to eat them. Once eaten, the Ghosts' eyes retreat back to the Ghosts' Nest so that they can respawn.
- Pokémon: While most Ghost-types are not, strictly speaking, spirits of the dead, several of them still fit this trope:
- This goes all the way back to the original Ghost-type Pokemon Gengar, whose personality has been expanded from being a simple prankster to being actively murderous.
- Banette, a cursed doll looking for revenge on its former owner.
- Spiritomb, who is made up of the souls of 108 criminals and is part-Dark type.
- Froslass, a Yuki Onna who freezes attractive men and displays them as trophies.
- The Litwick line, ghostly flames that lead unsuspecting travelers astray while burning their souls as fuel.
- Trevenant, a treant who traps people in their forests to be eaten.
- Palossand, a haunted sandcastle literally built on the bones of the dead.
- Quest for Glory IV: Wraiths are the malevolent ghosts of greedy and cruel individuals unable to pass on after death, and harbor a deep hatred for the living. Just being near one without some sort of protection will sap the Hero's strength so long as they are on the screen, if not kill him outright. They are among the toughest enemies to fight in the entire game (especially the Master Wraith, which slew the Paladin Piotyr prior to the events of the game). Fortunately, they're bound to either the place where they died or their grave, so while extremely dangerous, they can be avoided.
- Sonic the Hedgehog:
- In Sonic 3 & Knuckles, Act 2 of Sandopolis Zone takes place in a pyramid. Sonic accidentally opens up a capsule filled with ghosts that start off harmless, but become more threatening the darker the pyramid gets. Pulling light switches temporarily turns the light back on and scares the ghosts away, but the ghosts come back when the pyramid gets darker again.
- In Sonic Adventure 2, ghosts, known as Boos, are common enemies in Pyramid Cave, Egg Quarters, and Death Chamber. In the same game, King Boom Boo is a giant ghost who serves as their leader and a boss. Knuckles fights him, and King Boom Boo is weakened when he is exposed to sunlight. He has a small ghost following him around to hold an hourglass that temporarily lets light into the arena.
- In Sonic Heroes, Pumpkin Ghosts appear as common enemies in Hang Castle and Mystic Mansion. They can usually be found in confined spaces, such as behind unlockable doors, near switches, or in corridors. They can randomly appear and vanish at any time, and laugh wickedly at the player when they touch them, removing their shields or making them lose rings.
- In Super Mario Bros., the Boo Buddies are villainous ghosts who dwell in haunted houses and ships and attack Mario when he enters these places. However, they are extremely shy and will cover their faces when Mario looks at them, only creeping up on him when he's turning away.
- Warcraft III:
- Banshees are the ghosts of High Elves slaughtered by the undead Scourge and raised up by the Lich King, who gave them voices to avenge themselves on his enemies by shrieking at them (and going by their voicelines, also a literal case of And I Must Scream). Their ultimate ability Possession kills them in exchange for permanently controlling an enemy unit.
- Ghosts, Wraiths and Specters are the neutral monster version, having similar spells (including Possession). However, they don't have voices, only sad moans.
- Shades are unarmed ghosts used as scouts for the Scourge, made by sacrificing an acolyte.
- DuckTales (2017): Scrooge's ghostly butler Duckworth usually just looks like a transparent butler. However, whenever the occasion warrants, he can transform into a very frightening demonic apparition.
- My Little Pony 'n Friends: In "The Ghost of Paradise Estate", a monstrous and malevolent ghost chases the ponies around the Estate, turning itself into horrifying shapes and stalking them through their house in order to scare them into fleeing it.
- SpongeBob SquarePants
- A recurring character is the Flying Dutchman, a ghostly pirate who enjoys scaring Bikini Bottom residents and sometimes threatens to steal their souls. In some episodes, he's portrayed more sympathetically however.
- In the episode "Graveyard Shift", Squidward makes up a story about a murderous ghostly fry cook with a spatula hand called the Hash-Slinging Slasher to scare SpongeBob. At first, it looks like the Slasher was Real After All, but it turns out to just be a new employee who just so happened to be hidden in the shadows. And that ol' rascal Nosferatu.