Several people are terrified by Boos. It pretty much all boils down to the fact that they only chase you when you're not looking. It only leaves the door open to Fridge Horror.
This series introduced the concept of spikes = instant death in video games. Good thing everything causes Mario to go into Death Throws. Doesn't stop some kids from being scared by the thought of falling and getting impaled on spikes, and the resultant saturation of spikes in video games as a whole causes nightmare fuel filled scenes in video games where they DO impale you.
Super Mario Bros.
The first Super Mario Bros. gave us the Minus World, a world no man is intended to go to and has no escape, unless you count drowning to death or the reset button as a method of escape.
The castles in the first Super Mario Bros. game for the NES are really, really terrifying. There's just something about them; the lifelessblack background, the pointy-looking lava that doesn't move, the revolving sticks of fire, the fireballs that come as you approach Bowser's lair, Bowser himself (especially later on when he learns how to throw hammers)... and that music. THAT MUSIC. Some of the castle levels are mazes that will repeat endlessly until TIME RUNS OUTAND YOU DIE. (or until you find the correct path)
The famous cave music probably creeped out more than a few kids.
Super Mario Bros.: The Lost Levels (Japanese Super Mario Bros. 2)
8-4 and D-4 both have two Bowsers in one castle (one of them is fake).
Super Mario Bros. 2 (USA)
The friggin' Hawkmouth in Super Mario Bros. 2 (the one that acts as an end of level gate) scared the crap out of some in the end of World 7-2 when it flew off the wall and tried to chase them!
And then you get past the door to confront Wart — and the music changes to this creepy, disturbing horror/techno mix that just messes with your concentration while you have to catch vegetables in midair and throw them into Wart's open mouth (as opposed to the other bosses where you just had to hit them with weapons).
Phanto. Creepy pumpkin masks that move really fast and chase you.
The Angry Sun made some too scared to play past World 2.
Some were also afraid of the Podoboos in the World 1 mini-fortress.
There were also some terrified by the Hot Foot in the first fortress of World 4.
The first fortress in World 7, since the entire place is empty. No enemies whatsoever (barring the boss). Even worse is that one can see where the enemies would be, giving the feel that it was just suddenly abandoned.
In the Super Mario All-Stars remake of Super Mario Bros. 3, World 5's blue mini-fortress has both a lava floor and a ceiling. It's even more unsettling considering that in SMB 3, lava isn't merely a harmless curtain for the top of a Bottomless Pit; rather, touching it kills you instantly, even if you're Super Mario. Or powered-up with the invincibility star for that matter.
Boss Bass from Super Mario Bros. 3 and Super Mario 64. Super Mario 3's Boss Bass in particular has this habit of jumping right out of the water, snatching you right off the surface and swallowing you whole in one gulp.
And what makes it even more never-racking that by swallowing you whole in one gulp, means that no matter what power-up form you're in, being swallowed and gulped is an instant death regardless.
Super Mario World
In the final battle, Bowser is seated in a hovercraft which is painted like a clown's face. After Bowser is hit a number of times, he flies forward, so that the screen zooms in on the hovercraft. Push the pause button at the right time, and there is a screen full of clown face.
Then the said Clown-faced hovercraft in its final phase with its eyes being butch and angry while still smiling as small veins pop out at the side of its head, all the while trying to pound and crush you.
What got to some was Mario/Luigi's death sprite. Maybe they went red/green with shock, but to some, they just looked... odd.
The big green bubbles in the Vanilla Ghost House freaked many out a bit. They were large, invincible, and always got in the way, and if even two closed in on you, you were screwed.
The way secret keyholes grow so huge and then swallow up Mario is just plain freaky. The accompanying music only makes this worse. The GBA port makes it even worse, because the music in that one has a louder bass line at the end that acts as sort of a Last Note Nightmare.
The Big Boos from Super Mario World gave some fright as a kid, but the Mega Moles just continuously pop out and attack.
The graphics in Super Mario World. Most of the time, they were gorgeous. But many of the enemy sprites were just wrong. The weird, hunched-over shell-less Koopas, the odd posing and so-smooth-it's-creepy animation of the Charging Chuck, the weird stick legs on the Koopa Kids... not to mention the fact that when you die, it looks like Mario is bleeding from his eyes! Accompanied by a Scare Chord, no less!
Those creepy looking Bowser statues in Bowser's Castle if you took one of the rooms, only to encounter a live jumping one.
Lava appears in some athletic/overworld levels. Except, due to palette differences, it's colored brown. Functions exactly the same, except, well, what is it? Mud? Melted piece of the ground? So bacteria-filled and acidic that bubbles come out?
It's molten chocolate. That the stuff is only encountered on Chocolate Island is something of a giveaway.
Big Boo in Super Mario World has a placeholder sprite for use before the final sprite is loaded. If seen at all, it's likely for a split second. However, it's an empty, soulless emotionless face that for some falls right into the Uncanny Valley.
Which technically, just happens to be the same face Big Boo makes when facing it, just without being covered by the sprite's arms.
Super Mario 64
The Mad Piano in Big Boo's Haunt, when invoked, it grows teeth and tries to eat you (as seen above). To make it worse, it sounds like someone angrily banging their fists on the piano keys. Much of Mario-related trauma has come from that enemy alone. And to add insult to injury, one of the red coins is located behind it.
The Big Boo fights and the music were also something else to be scared of, not to mention the creepy calliope music from the carousel.
"Ghosts...don't...DIE! Can you get out of here...alive?"
The entry to Lethal Lava Land (remember, that flaming face painting◊?) was frightening enough to scare you out of the room. Worse yet, it is the same face that shows when you lose a life from running out of life or by hazards, in other words Bowser attempts to scare you.
Mr. I. No matter where you go or how fast you run, he's always WATCHING YOU.
What happened when you ran into a door when you didn't have enough stars to open it. Bowser cruelly laughs at your misfortune.
Bowser himself. It's just the way his model looks, always with that evil look on his face, and if anything, the polygon look just made him scarier.
He's especially frightening in the final battle, due to his green glow, his three varieties of fire breath attack, his seismic stomps, the fact that one bomb isn't enough to end him this time, and especially the music.
That GIANT FREAKIN' FREIGHT TRAIN-MONSTER that is the Chain Chomp◊. Shigeru Miyamoto designed Chain Chomps based on his own fears of being bitten by dogs. Thanks, Miyamoto, for making sure your own nightmares fuel other people's nightmares.
Super Mario 64 DS manages to make Big Boo's Haunt even scarier by adding the area where you get the key to unlock Luigi. You jump in as Mario and arrive at an area that seems like a rather simple Lost Woods like level, where a wrong door will take you to the beginning of the level. Wouldn't be too bad if it wasn't for the absurdly frightening laughter King Boo keeps dishing out as you run through the level...
The only truly scary parts would have to be Eyerok, the Shifting Sand Land boss. The two big-ass rock hands with eyes on the palms. The ones that try to push you off the slender platform and into a pitch black emptiness.
Dorrie, the creature from Hazy Maze Cave. The big blue dinosaur with the red slit mouth and tiny eyes that a nearby sign claims that will eat you.He doesn't, but still. Thankfully turned into Nightmare Retardant in Super Mario 64 DS with the addition of swim goggles, as well as making his face more Yoshi-like.
Mario's drowning animation. Mario desperately struggles and seemingly making failed attempts to gasp for air in blind panic and agony, with the game fading out as Mario's corpse is going limp. The poison gas death (the area mentioned above) is no better, with Mario grabbing for his throat, then falling on the floor with the screen fading out as he lies twitching (apparently still alive) in his final moments on the floor. The toxic area was really the worst in that, as anytime you are breathing it Mario would cough and slowly choke as if struggling for air.
Playing with Gameshark in Mario 64 can get you very disturbing results. This video, one of the many that refers to Gamesharking in Mario 64, leads the watcher to the ultimate nightmare, especially as Mario enters the castle lobby.
The painful cry Mario did whenever he got hurt in Mario 64.
In Super Mario 64 DS, if you play as Luigi and turn invisible in a Mirror room on the third floor, you can go through the door that is supposedly the reflection of the entrance door. Going in there, you find yourself in a white abyss with nothing but you, the door, and a power star.
The underground/water town in Wet Dry World, along with the background to the level (A city of flat-roofed buildings). Completely deserted excluding a lone Bob-omb. What exactly happened there?
Justified slightly in that the background looks like an ancient city, so the town could have been empty since ancient times. But considering that it probably flooded every five minutes, it's no surprise it went empty. Perhaps some evil person got his hands on the water crystals...
This one is a long shot, but the main HUB itself could be creepy if you think about it. You're in a big castle/mansion.....all alone....except for the Toads.
When you get the Power Star from atop Bowser's submarine, the sub disappears from Dire Dire Docks for stars 2-6. And that Bowser door opened underwater... becoming a big black hole that SUCKED YOU IN if you got near it.
The secret under the moat. It takes place in a gigantic room that is 95% nothingness, with the level itself taking place along the edge.
The Game Over screen. Mario's face, contorted in pain and exhaustion, against a dark red backdrop, with a warped excerpt from the Main Theme playing in the background, was rather overstimulating for some younger players.
Super Mario Sunshine
Super Mario Sunshine, an otherwise rather bright game, features a level where you have to go underwater (thus, making it a Timed Mission), and clean the teeth of a giant eel; complete with poisonous bubbles and a whirlpool that threatens to suck you in.
The Gooper Blooper battles from Super Mario Sunshine. Mario is fighting a giant squid who uses his tentacles and ink that summons slimy enemies to attack. The method of defeating him is to jump on each of his tentacles and graphically pull them off one by one; after doing so, the pulled tentacle will wriggle wildly before disappearing.
Phantamanta is a pretty frightening boss, and a pain to beat as well. It's a borderline Eldritch Abomination that can move over ANY surface like some kind of shadow and leaves a trail electric goo, and when you spray it, it splits up, spray them and they split up, spray THEM and they split up! Then, once you got it into its SIXTY-FOUR parts, they all turn red and charge at you like mad!
In New Super Mario Bros., Bowser is fall into lava in the first world. Not much different from what happened at the end of every single castle in the original Super Mario Bros... until the game proceeds to show him desperately flailing in the lava, yelling in agony, and emerging with all of his flesh melted off. Totally unexpected and freaky as all get-out.
Mario's next line, immediately after the whole debacle? "That's-a so nice!"
Later on in the game, it turns out that he's still alive and continues to live on as a skeleton. Which meant he actually got to feel his flesh burn off. Wow, Nintendo.
The giant caterpillar in the Gusty Garden Galaxy of Super Mario Galaxy. The way it's almost realistic in appearance in a game with an intensely cartoony art style creates an effect similar to the Uncanny Valley, and it makes some genuinely disconcerting high-pitched noises. The enormous nose and buck teeth do little to diminish this.
When Mario's hand rises up when he sinks in sand or toxic waste, all while hearing him drown.
When Mario touches dark matter, he slowly disintegrates, and his life bar isn't empty until AFTER Mario is completely gone. He feels the whole thing!
And then there's dying of electrocution, which leaves only a skeleton.
The Gringills in the Beach Bowl Galaxy. The giant ones with googly eyes and teeth almost as long as their head.
In a little more detail; you're swimming through a beautiful galaxy full of clear water and cute penguins, not many enemies at least not at first, but then you come to a dead end and a giant Gringill comes EXPLODING out of the darkness and flails about with another little one above it. It can be killed with Koopa shell, though.
The hovering, screeching Cluckbooms. There is just something vaguely disturbing about them...
The Bonefin Galaxy, home to the giant skeletal shark known as Kingfin.
The giant jellyfish. Sure, there were only two, but each one was in an rather off-putting location: the first in the Bigmouth Galaxy, where more and more ghosts kept popping out of nowhere underwater, and the second in the Deep Dark Galaxy, where you HAD to swim RIGHT PAST IT because it took up most of a certain passage. (Oh, and both galaxies had some of the most ominous-sounding music in the game.)
Also in the Deep Dark Galaxy is a planet accessible by a cannon, which is basically a tiny version of the first planet in Gateway Galaxy. It's kind of odd in the first place to come across something like this, but if you jump on a nearby screw and spin around, the planet will deflate like a giant beach ball. It even rewards you for doing this with coins!
Between them, Mario and Bowser wind up destroying the universe.
The music that plays when you wake up the Dino Pirahna is very unsettling, as is the fact that you are on a small planet with the possibility of being plowed into by a giant, blind beast. The Dino Pirahna itself is no better, especially when you get it angry. And when you defeat it, the idea of having just killed a baby doesn't sit right either.
Also, when Dino Piranha dies, its red skin turns a pale purple. Anyone who knows anything about babies or humans in general knows that skin turning blue is not supposed to happen.
In one of the later areas, you come across FIERY Dino Piranha. The guy was freaky enough the first time around, but, ON FIRE?
Luigi's deaths in SMG. Poor Luigi sobs hysterically as he falls to his death.
Even worse is when he falls in quicksand or the swamp goo. His scream sounds distinctly like "Help help can't swim!"
Also, right before Bouldergeist explodes, his uvula pulsates, his head shrinks, and his eyes triple in size... and he explodes...
The NPC bees are cute, but take a close-up look at their faces...
The Lumas' cycle of gorging themselves, and then committing suicide by exploding into a new celestial object. They are eventually being reborn somehow, but these guys are happy that they are exploding.
Outside of the small planet the boss Kingfin resides in, a random Toad Brigade ship. This doesn't seem scary at first, but then you realize the ship is empty and the toads are nowhere to be found, and a giant, Jaws-size skeleton fish down there has teeth that look sharp enough to rend flesh. Uh oh.
Super Mario Galaxy 2
Cosmic clones in Super Mario Galaxy 2. The ones in the previous game were simple Mario and Luigi clones that served as racing opponents. In this game, they follow your every action with a delay of a second or two. If one catches up to you or you bump into one, it hurts. You can't stop for even a quick breather or you'll get hit. And they keep coming. More and more of them get spawned every few seconds, leading to a seemingly endless chain of them. Even the nearby signs are afraid of what they can do. And worst of all, their corruption extends as far as Luigi's Purple Coins...
They mimic their movements perfectly, a few seconds after they do. You touch someone on the shoulder, they touch them seconds later. You pick something up, they mime picking it up themselves. And if you stand still, they collide with you, exploding into dark energy at point-blank range. And until you, or possibly somebody else the comet is focusing on, finishes an arbitrary task, they spawn forever. Following you everywhere. And when you think about it, aren't the other comets also Fridge Horror? Just think of what happens when, say, the Red Comet gives one arbitrary person a time limit to do one task before dying.
In several late levels, giant lava monsters suddenly rise up from out of nowhere and engulf your platform in their mouths. The last one is particularly memorable.
In one galaxy, a group of penguins are out swimming, watched over by a couple of larger penguins. To get the non-secret star in that stage, you must hit a switch that causes the entire area to freeze solid. It's not just the surface; you can see them under the ice, frozen in midstroke.
In the Shiverburn Galaxy, if you change the camera to first-person mode and look toward the cliffs above you, there seems to be three mysterious shadowy figures on the cliff, watching you, and following you. You can read about it here.
They're supposed to be trees. It doesn't help though, because they don't look at all like trees. And they have glowing eyes. Brrr.
The file names? "BeyondHellValleySky is where they reside, and HellValleySkyTree is the names; the ominousness of the trees were enough, but those names make them worse.
The swirling spirits in the background in the ghost levels.
Magmaarghs (a much larger version of Blarggs from Super Mario World). They're huge, hideous creatures made of lava who look incredibly deranged, with strange eyes and huge mouths, and when they try to collapse into Mario or Luigi, they make a very disturbing roar until they lose their form in the lava.
Super Mario 3D Land
An Easter Egg: In the yard at the end of any ghost house, waiting long enough causes a ghostly figure to appear in the background just behind the fence and will vanish after a few seconds. This figure doesn't actually do anything and cannot be interacted with, but what makes it creepy is that the thing resembles the Shiverburn Galaxy figures. They're not trees. They're still watching. And they're getting closer.
Even worse, it could be Slenderman, in a frigging Mario game. And as a bonus, it opens its mouth before disappearing, as if trying to scream at you... brrr.
The connection between the spirit and the [HellValleySkyTree]... there's also a UFO visible if you wait a minute at 1-3. What other freaky stuff has Nintendo put in these games? Are they... are they trying a secret subplot told through weird Easter eggs?
Come to think of it, that UFO...we've seen a UFO like that before. Specifically, one that helped Bowser to airlift Peach's Castle in the first Galaxy game... Yes, others appear in later levels, but that first one that helped kick everything off—Bowser did not just happen across it on his own...
The cosmic clones. They mimic Mario's quotes, but in a higher pitch with added distortion. When they say "Let's-a go!", it sounds like they're saying "Time to chow!". Yikes.
New Super Mario Bros. 2
The Boohemoth, a massive Boo enemy, is bigger, chubbier, and his eyes don't look at all like the charming dot eyes that normal Boos have, but more into the Uncanny Valley. Although he only shows up in two Ghost Houses, he'll appear without warning with a Scare Chord and chase you. He too stops and hides his face when Mario or Luigi looks at him, but every so often he'll peek and approach anyway. Thankfully, he only appears in two levels.
In World 5-Castle and World Star-Castle, Mario has to make his way across a lava-filled platforming level. The kicker? He has to avoid the Koopalings' special petrifying gaze. If he's not hiding behind a wall, one wrong step and he'll most likely freeze, and fall into lava.
As cited from a Miiverse post, the Shiverburn figures are back. They can bee seen through a reflection on a Clear Pipe Cannon on the last main level, The Great Tower of Bowser Land.
The post? "Anyone remember those mysterious faces on the top of the cliffs in SMG2? Or the mysterious face in the ghost house in SM3DL? Look closely at the reflection in this photo. Tell me what you see."
The way the enemies die in Super Mario Land is actually kind of creepy. Unlike the NES Mario games, where enemies generally flip upside-down and fall off the screen when you jump on them, here they lay on the ground, flattened and dead for a few seconds, before flopping off the screen. It gets worse with the Koopa Trooper analogues, which explode when they die.
The "Daisy"s at the ends of Worlds 1 through 3 of Super Mario Landthat are actually monsters can make the player jump a bit.
The Thwomps from Bowser's Castle in Mario Kart 64; it's that disturbing Evil Laugh. The green one in the cell is scarier for some reason. Luckily, they aren't scary in the Wii version's remake.
Mario Teaches Typing 2, like Mario 64, featured the floating disembodied head of Mario. Unlike the Mario 64 version, this one goes back and forth between cracking jokes and being amusing, to being just plain unsettling at times.
The GBA puzzle game Mario vs. Donkey Kong features a relatively realistic 3D rendering of Mario facing off against cartoony Thwomps and Shy Guys, and is brought up at this point in the page due to its Galaxy-like series of disturbing death animations. The default animation (for example, stepping on spikes or touching a Shy Guy from the side) has Mario tilt briefly before he falls face-first into the floor (or spikes!) and stops moving. Then there's the specialty animations for dying to a fiery or electrical attack, which don't pull any punches about how terrifyingly painful it must be for poor Mario.
There are three different "death" tracks in the game's BGM. While the first two apply for "standard" deaths (the second is used for getting burnt by lava), the third is used for the most horrifyingly painful and gruesome (for Mario standards, that is) death animations, such as getting squished by a Thwomp, falling from a high place (with Mario falling on his head as a result) and, last but not least, getting electrocuted to death. In fact, you can tell the various deaths apart by listening to the different pitches of Mario's variants of his classic "Mamma mia!". The first is "standard", the second is "exhausted", and the third is "a mixture of pain and horror".
Mario Tennis was the game that debuted Waluigi. In his debut, Waluigi, not only was pretty creepy looking, but made extremely weird noses all of the time, almost like a psychopath groaning in pain or delight. Whenever he scored, his celebration would have him making his eyes glow and flash purple, all while bearing the demented grin frozen into his face. The glowing eyes, to this day, remain unexplained.
In Mario Power Tennis, when Yoshi wins a trophy, there's an animation in which Luigi brings it to him. Things go awry, and in the end Yoshi has swallowed Luigi. He doesn't get spit out. There isn't even an egg. He never escapes.
Another one involving Luigi, Luigi delivers a trophy to Shy Guy. While walking toward Luigi, Shy Guy suddenly trips and his mask falls off. Only Luigi sees what's under his mask, and he is terrified. What is under a Shy Guy's mask!?
The end of Mario is Missing!, when Bowser is defeated, may scare some young children. You don't fight him, he comes out of nowhere and is shot out of a cannon, innocent enough. It's cartoony. Then he falls into the ice, freezes up, is covered in snow, then shatters.
Also, one of Peach's screams when she is electrocuted sounds like a realistic interpretation (i.e. screaming bloody murder) of feeling that type of excruciating pain in contrast to some of the other screams. Think about how she and the others feel in a more realistic way after that.
The Game Over theme from Super Mario Kart. What's scary is that if you lose all your lives, the screen darkens, your character vanishes, then "GAME OVER" drops in ghostly-like letters, with that nightmarish music playing in the background.
Super Mario RPG: Legend of the Seven Stars
In Super Mario RPG, there's a room in the Sunken Ship with a Mario clone that seems pretty harmless, like any other NPC. Except that said Mario clone TURNS INTO A GREAPER out of nowhere, and you enter battle.
When you initially arrive at Seaside Town in Super Mario RPG, there is definitely something off about the place. The townspeople all look identical, and display disturbing behavior, like stopping mid-sentence to quietly converse with each other, and watching you sleep. It eventually turns out that a Smithy Gang member named Yaridovich took over and impersonated the entire town.
Smithy, himself. Imagine a cyborg-bearded-giant-king-thing, with More teeth than the Osmond Family, and a couple of replaceable heads, each just as creepy as the original.
This was the first Mario game to feature apparent actual death of NPCs, mainly Toads.
Cackletta possesses Bowser and turns him into a mutant hybrid of the two. And to fight her, you have to go inside Bowser and fight Cackletta in the form of some spirit/gas thing and attack her heart.
Joke's End. It's the Slippy-Slidey Ice World (minus Frictionless Ice) of the game. In contrast to the smiling faces littered all over the other areas, Joke's End has expressions of despair littered all over. Frozen. It wouldn't be so bad if this weren't the music.
The statues found in Joke's End depict great suffering, with hands placed over their ears and tears streaming down their cheeks. It's almost like the place is the hell of the Beanbean Kingdom. And it is. The theme of the Beanbean Kingdom is laughter, and Joke's End is the final resting place for cruddy jokes. The miserable-looking statues covering their ears may be meant to represent just how horrible a bad joke can be to the people of Beanbean.
Many of the places that Cackletta involves herself with? Yeah, they become this.
The Mario Bros.' first visit to the Beanbean Castle Town. The houses and buildings are all wrecked and innocent civilians lie on the ground like they're on the verge of death. The music makes it feel like you're walking in a graveyard.
It gets worse. You end the game with the town in this state. Yeah after having a nice town for a good portion of the game, it's reduced to this sorry state by Bowletta during the endgame.
Partners in Time
The Shroobs. They are basically evil mushrooms that invade the Mushroom Kingdom because their home planet is a barren wasteland. They reduce the Mushroom Kingdom to rubble, and take it over. Then, they begin taking the population and turning them into FUEL FOR THEIR UFOS!?WHAT THE HELL NINTENDO!?!
The Elder Princess Shroob: she is a giant mutant with numerous tentacles for legs and for arms, and a hideous face. To make it worse, she attacks by even shooting down her own men... Also, her battle music is a strike in "Soundtrack Dissonance".
Toadwood Forest and the Vim Factory. The Shroobs are using the Toads' LIFEFORCE to power their spaceships. Also, after defeating the Swiggler, you can still find Toads strapped to the trees!
When Peach first goes on her trip, she is accompanied by two Toad attendants, Toadiko and Toadbert. By the time you encounter Toadiko, she is already near-lifeless because the Shroobs were sucking her vim away. Then, she is found out and turned into a Shroob mushroom, presumably dying (If she doesn't, it's even worse). Toadbert traumatically loses his memory for most of the game, and is promptly turned into a Shroob mushroom as soon as he recovers it. In both cases, this is softened by the fact that they, like all of the Shroobs' victims, recover (Toadbert's even returns as comic relief in the third game), but still, this is some hardcore stuff, especially considering we don't even know how long they've been like this.
Inside Yoob, you can see him wince in pain when the Babies use the hammer or the Baby Drill. The latter is especially wince-worthy if you consider that Yoob just had something drilling into his flesh and is moving underneath it.
Bowser's Inside Story
Mario & Luigi: Bowser's Inside Story. Much of the game takes place inside Bowser's body. Which is strangely maze-like and platformer-esque. You have to manipulate Bowser's organs at times to get Bowser moving or affect him. The idea that Bowser has these characters running around inside him affecting his bodily functions and messing with his insides is very grotesque. Plus, some of the enemies are odd, virus-like versions of regular enemies such as Goombas. Enemies that Bowser inhales can damage him internally by attacking his body! And all the Toads are infected with a disease that makes them inflate in size and roll around uncontrollably!
The final boss fight. Fawful has transformed himself into some really freaky spider-like/bug-like thing, and is inside Bowser's body, transforming his stomach into something mutated looking. And his face... It's really disturbing to think about.
The song played in Fawful's Castle from Bowser's Inside Story.
The Dark Star in general is creepy — it is literally an embodiment of evil that can absorb other beings to use as a source of power, as it does to Fawful! Then he turns into an evil version of Bowser sporting a mohawk! Oh yeah... IT SHRIEKS.
The cutscene where the Dark Star chokes the Mario Bros. with its dark energy.
The Final Boss. Bowser attempts to wish Mario and Luigi away with the Dream Stone, but when that fails he settles on absorbing its fragments to turn into a Reality Warper capable of doing anything he desires. Just because the Dream Stone embodies good dreams doesn't mean those good dreams are benevolent....
The last segment of Neo Bowser Castle. Things start off when the Mario Bros. find the source of all the nightmare veins. Then Mario enters Bowser's dream, which is about as disturbing as you'd expect a dream of the Koopa King to be.Themusic really sells the whole thing.
If Yoshi is hit, Baby Mario is suddenly caught in a flying bubble, wailing desperately, as the player tries to get him back before the enemies catch him and fly away with him.
The threat of being eaten occurs quite a bit. A boss battle occurs in a frog's stomach and Piranha Plants will try to swallow you hole. There are also a few chase scenes in which a gigantic Chain Chomp is out to eat Yoshi.
In the beginning, Yoshi must turn himself into a helicopter and fly across a bottomless pit. Every so often, Kamek will swoop behind Yoshi and ambush him from behind. He also does this in the Extra Level from World 5.
There is an optional chase where Tap-Tap the Golden, a large spiked undefeatable enemy, is chasing Yoshi across a rocky, lava filled area, as the screen ever so slowly moves to allow him more area to move. It doesn't help that before entering this chase, if the player wants to receive helpful information, all they get is "RUN AWAY!!! HURRY!!!" in dramatically huge font.
What arguably makes this even worse is that you're being chased by a boss that's nigh-invulnerable, and is large enough that you can hear the ground quaking from every step that it takes. Oh sure, your eggs manage to stun it, but that's about it. Not even it falling down a hole to its doom can stop it; it just springs forth like a proverbial bat out of Hell, and continues to chase you, its smile almost taunting you.
Before the final battle is another chase scene, only this one is an autoscrolling level which takes place in a creepy playroom-themed dark hallway. Kamek constantly appears from out of nowhere in various places and will zap you with his magic wand. If he misses, he will turn blocks into small enemies or stars. You can throw eggs at Kamek but he will just reappear somewhere else. All this happens while impending doom music plays.
In the final battle, where Baby Bowser, in an eerily designed toy room, attempts to ride (and therefore injure) Yoshi. After he has been defeated, Kamek turns him into Big Bowser. Big, meaning the castle he had occupied is completely destroyed by his transformation, and he could probably crush Yoshi with a single finger/claw. The transformation and battle is accompanied by rather horrifying music, if not the entire series, and the battle is pretty much Yoshi trying to hit him with large eggs to push him back, while he is slowly coming towards you. When he is hit, he is indeed pushed back, only to then run at full speed towards Yoshi, who is standing on a small ledge (which is being destroyed by the boulders that fly in the air from Bowser's roars). If Bowser comes close enough, his stomach obliterates the ledge, leaving Yoshi unable to do anything but plummet to his death. This can be extremely scary when one is desperately trying to get him further back, knowing that he will run at full speed afterwards.
What makes this even worse? When he has one hit left, he'll continue to run towards you, and will not stop until he collides with Baby Mario and Yoshi.
"Touch Fuzzy, Get Dizzy."
Your primary method of attack in this game is that you eat your enemies, and then transform their digested corpses into ammunition, which you then throw at their comrades, who no doubt just watched you consume their friends seconds earlier. If that's not just a little bit disturbing...
Consider that this ammo is eggs. Yoshis use their unborn young as ammo.
If an egg are unfertilized then no, that is not the case.
The sound of the Lunge Fish is one of the most terrifying sounds in video games.
The Lunge Fish itself. It just comes right out of nowhere and eats you, killing you instantly.
Those giant Chain Chomp heads that fall from the sky. Not only the fear of getting hit and falling into the holes they leave, but those faces.
Gargantuan Blargg and Nep-Enut can be pretty scary for kids too, with this giant red/blue thing popping out of the lava/water out of nowhere, especially if you don't realize there are eyes there.
Neglecting to retrieve Baby Mario in time rewards you with and image that consists of the Toadies carrying Baby Mario away against a black background. The noise they make doesn't help.
On that note, the "Game Over" screen deserves a mention here. It shows "GAME OVER" in a deranged font zooming in and rotating in random directions. The same animation repeats itself several times afterward until you either continue the game or shut it off. The depressing piano ditty that plays under it and the fact that SNES games with pre-rendered 3D graphics were in their relative infancy only make this worse.
Inside the Magma Castle lurks an enemy not found anywhere else in the game—the Attacky Sack, a colorful, invincible patchwork ball with razor sharp teeth. t=2m30s Watch this, and be enlightened.
Two words: "Blargg's Boiler." Everything in that lava-filled hellhole is a bit scary, whether it was the giant monsters with GAPING MOUTHS that jump out of the lava and ROAR AT YOU or the lava-ghost things... the noise they make... that SHRIEK...
And then when you lose a Yoshi, these cutesy-yet-horrible flying things carrying it through the air to the dark castle as tears fall from its face...
The Cheep Cheeps in the jungle levels scare some.
The last page of the game has four different themed castles, each of which is terrifying in its own way. Mecha Castle has machines that can crush or flatten you. Lift Castle is filled with buzzsaws that try and kill you. Ghost Castle, probably the least creepy, is full of Boos and other ghosts. Magma Castle is filled with lava and some of the creepier enemies.
Mecha Castle, however, wins in Nightmare Fuel, as it features blades that pop out from walls and chase you, spikes, some saws, and the aforementioned one hit kill machines that move particularly realistically and violently. Magma Castle would be second, but it has a more epic and dungeon feel to it.
Big Blurp. It's another enemy that can eat you. And it comes in two flavors! The red one who jumps out of the water and the blue one who spits water to try and throw you in. Trying to get all the fruits possible in the previous section is a normal practice here.
The death screens, featuring a crying Yoshi being carried away into the depths of a dark castle... very dark for a game like this.
The death screens alone are bad, but the music that plays on the Game Over screen is even worse!
How about the Bone Dragons themselves? And the music the plays on P.2 - Cavern itself...
Level 4-2, "Jungle Puddle," is all good and fine for the first part. Then you get to the second part, with giant, invincible Blurps that eat you up, instantly causing you to lose that yoshi. Those things caused nightmares in many a gamer back in the day, especially the younger ones.
Level 4-3, Piranha Grove. An entire forest of Piranha Plants, with you in the middle.
The insta-death machinery in Mecha Castle.
The castle itself no matter what course you're on.
Wario Land Series
The other Wario Land examples have nothing on the Really Final Stage of Wario Land II. The enemies petrified inside bubble gum with disembodied, realistic eyes, ears and mouths everywhere. It's like the inspiration for one of the rooms in Yume Nikki.
Let's start out by saying that in Wario Land 3, nothing can kill you. Being hit by enemy attacks causes some kind of inconvenience, such as knockback or a status effect (being set on fire, for example, causes Wario to run uncontrollably until he touches water or until the fire envelops him, giving you a short time to walk around, invincible and able to use the fire to solve certain puzzles, at least until it reduces him to a pile of cinders. Which he walks out of completely unharmed, being indestructible). After retrieving the Plot Coupons, you return to the temple holding the being that has advised you over the course of your quest to find out that, on top of simultaneously being the Treacherous Advisor, the Big Bad, and a Monster Clown, he is the only thing in the game that can kill Wario. Seeing the Game Over screen after a whole game without it can render some kids unable to finish the game.
That ghost thing in The Vast Plains. It does not look harmful, but if you get close enough to it, it actually zooms down on top of you and makes the screen around Wario and the ghost all black, all the while closed-eye grinning. And the only way to reverse it is to bump into a wall or something similar.
The snakes in some of the levels. It's just that, after the snakes rise from their urns, their heads turn red, make a cacophonic hissing and spew fire from their mouths.
And the fact that she absorbs the black cat (who is actually Princess Shokora) when it attempts to oppose her.
In general, most of the audio and sound effects in Wario Land 4 are incredibly bizarre at times. Then, there's the "HURRY UP" tune.
Many of the bosses in this game fall into Uncanny Valley, but Spoiled Rotten takes the cake. Once you get his health down to a certain point, he suddenly gets a disturbingly detailed face and huge, razor-sharp teeth.
The Wario World bosses. They're not creepy in the way the fourth game's bosses might be, but they fall so deeply into the Uncanny Valley that they just look totally wrong in all ways possible. The Mean Emcee looks bizarre, people have mentioned the Winter Windster as creepy on the series page, and Clown-a-round... well, it looks so much like it's made of plastic that it seems unnerving. The fact its face is located in the top of his next doesn't help matters either.
As for the Brawl Doll, kill it with fire. As seen here, it even laughs and turns its head 180 degrees when Wario approaches it.
Chortlebot in general. I mean, it's a flying, robotic clown head that tries to kill Wario with a flamethrower, and laughs maniacally while doing so! And it can be a pretty tough boss too, if you don't know what you're doing. What is it with Wario games and creepy clown bosses?
Specter Inspector. Once one player successfully finds three of the five creatures, the room lights up and the winner stands with all five as they all wave happily at the player. And then the camera zooms back to show that they're all trapped inside a painting in a dark room, as ghosts leer at it. Remember, this is the winner...
To say nothing of Bowser's Big Blast from Mario Party 2/4, and Cut From The Team from Mario Party 8. The tension alone makes the heart race in fear. Who will die first? Will it be you, or your friends? You're at the mercy of Lady Luck as you slowly step forward and meet destiny...
The entire Mario Party series is accidental nightmare fuel, especially the first ones. Any of the minigames involving Boos eating the losers was creepy.
When you think too much about it, hell yeah. There was Ghost Guess in the first MP where you had to guess which was the leader of a pack of Boos (a dozen or so) circling you. The game gives you the tip: the first one to start their dances is the leader. But then again, it's pretty hard to figure out which of them does it. And when you pick the wrong one... All the Boos converge on you and take you to God-knows-where. As soon as they're gone, so are you. Shudder.
And then there's Pedal Power, one of the games that used the infamous Scrappy Mechanic of "spin your Control Stick around like there's no tomorrow". You have to pedal a stationary bike to light up a lamp behind you before the Boo gets you.
Speaking of the original, some find the Options House terrifying! Mainly because of the freaky background music, but also the process that you go through to delete your save data feels like you're activating a nuclear missile!
Super Princess Peach
In Bowser's Villa, there are a couple of segments that contain several faceless Peach statues and a HUMONGOUS Thwomp that takes up the entire background. Before it opens its eyes to scan the area, you have to copy the poses the statues are in. If you fail to do so, you'll be sucked into his gaping mouth. Of course, you'll only be sent to the beginning of the segment, but still...
And then there's the wall of Langolier-like Boos.
Perry devours baddies to recover the Vibe Gauge. If there are no enemies nearby, one can stand still for a few seconds, cuing an idle animation where Perry latches onto Peach's head, to her vocal displeasure, regaining Vibe Gauge that way.
The Mad Boos and Mad Big Boos, which look positively Ax-Crazy.
In Bowser's Villa, there are several segments where you constantly need to avoid a pair of mechanical claw-like things flying in from the sides. Get caught, and you're treated to Peach being helplessly trapped in them while they begin a countdown to explode.And there's nothing you can do if you get caught.
Super Mario Bros. The Movie
Koopa coming on to Daisy. With his face and tongue getting... less human. (Early drafts suggest he was attempting to rape her.)
A fear of heights as well as death by falling makes playing Mario Galaxy and Mario 64 terrifying sometimesnote since Galaxy had falling into an endless abyss/sucked into a black hole deaths and 64 had falling damage.
The Super Mario Bros. Super Show! episode "Count Koopula" featured pretty creepy looking and sounding Giant Spiders that wore Snifit masks.
The episode "Ghosts 'R' Us" in Adventures of Super Mario World where Yoshi and Oogtar must save Mario, Luigi and Princess Peach from a haunted house. Their captor, Wizenheimer, isn't exactly Mr. Nice Guy. Probably because they keep screwing up his name.
The German Club Nintendo comic Super Mario in Die Nacht des Grauens(ENG) Super Mario in The Night of Horror features a zombie Princess Peach◊ with creepy black eyes and a pale, cracked face.
This image of Nurse Toadstool from the German Club Nintendo magazine has horrifyingSkintone Sclerae.