Banjo-Kazooie/Nightmare Fuel

The Dev Team At Rare Thought Of Everything when they made the Banjo-Kazooie games, and that includes this trope.

Well, these are the guys behind Donkey Kong Country after all, not to mention the copious amounts of subtle adult humor.

All in all, there's actually a surprising amount of disturbing content in both games. And as the characters themselves acknowledge, "this is a family game" - which might well be a shameless acknowledgement of what they managed to sneak past the censors.
The Game Over screen, true to Rare tradition, where Gruntilda succeeds at stealing Tooty's beauty: the former becomes a shapely, sexy villainess, while Tooty turns into a green monster and starts lashing at the camera repeatedly: "Banjo, your sister wants a word with you...now!". What makes it worse that, as it happened in Donkey Kong 64, the sequence is also triggered when quitting the game. All of this is backed up by the BGM, a brief rearrangement of Grunty's theme played by a Banjo.
- Made worst in the Xbox 360 demo of the game, where upon completing it, you see the Game Over cutscene, meaning in that demo, this is the canon ending.
Clanker's Cavern, Glitter Gulch Mine and Jolly Roger's Lagoon all share Psycho Strings as part of their BGM.
Some of the monsters in the games include worms that pop out of broken grates, life-vests with teeth, pipes with teeth and killer venus-fly-traps.
Mumbo's head isn't skull-shaped. Gruntilda cursed his face. And in Nuts & Bolts, Mumbo will juggle his eyes.
The termite mound in Mumbo's Mountain isn't as creepy as it first appears, but to those who are scared of insects, particularly insect nests, it does unnerve.
Treaure Trove Cove. A beautiful tropical island/beach area. Just be sure to stay out of the water... A great white shark, called Snacker, will suddenly appear out of the blue, and The Jimmy Hart Version of the Jaws theme kicks in. Also, one of the Jinjos, a honeycomb piece are underwater, several platforming segments take place across the water, and there are two occasions in which you absolutely need to swim for your life across a stretch of the sea. While this example may not be the most threatening in writing, it's fair to say that this was, to many, one of the most tense parts of the game.
- The fanged chests which contain items such as notes and even a jiggy might warrant a mention as well.
Clanker's Cavern. You start looking around a horrible, oily, grimy, scrap-metal waste tank-like area, in stark contrast to the bright and cheery atmospheres of the last two levels, and finding the only way to go is through a narrow pipe in grimy yellow-brown water. You swim along the pipe, until you see what's on the other side. Razor sharp teeth. A giant, metal shark is looking right at you as soon as you arrive.
- Not only that, but you have to go inside that metal abomination. Luckily, the creature isn't malicious in any way, but all the bloody looking stuff meshed in with all that rusty steel stuff looks rather discomforting.
- And don't forget this is where you are introduced to a new type of enemy. You see a round pipe jutting out of the walls. Now, you might want to try to go inside, or you might just dismiss it. In fact, when you near it, a giant green... thing just comes out and attacks.
- And the Mutie-snippets. Well, the area in which they're found. Suddenly, you're attacked by an enemy which is a deformed version of a previous enemy. And there's a tank in the middle of the room in which a strange bright green light floods out of the holes...
- The entire level in general forces you to explore underwater, worried about your oxygen meter, through grimy tunnels which seem to go on forever, and one even stops at a grill, revealing the main area, and the surface what's air you would be able to relish if only you had more time... And enjoy the realistic drowning animation.
  - And don't forget the exact bottom of the tank. Where Psycho Strings kick in to the music.
When you first face the snowmen in Freezeazy Peak, they don't look too bad from a distance, but when players get close, they will turn their way, with a really scary Slasher Smile on their face, evil eyes and they deliver a particularily nasty Evil Laugh before throwing snowballs at the player. And the only way to kill them is to master one of the most frustrating attacks in the game. They also are one of the few enemies that appear in more than one level.
The pyramid maze in Gobi's Valley there is a maze in a mummy king's tomb. Said mummy king is pissed off that you broke into his tomb, and forces you to complete the maze. The maze is very frantic and fast-paced, and you only get about 60 seconds to complete it, with frantic-sounding, panic-inducing music playing the whole time and tons of enemies trying to attack you. The camera also does sporadic rotations that make it even more difficult, not to mention the fact that the Witch Switch is located in a seriously hard-to-reach place that's about as far from the exit as possible. All in sixty seconds.
- While the maze itself isn't any more difficult than the one in Mad Monster Mansion, the consequence for losing is the player's controls are locked as the view goes first-person, looking straight up at the lowering spike ceiling...
Mad Monster Mansion: although many claim it's supposed to be a "goofy, kiddie" ghost house, that still doesn't stop it from being very frightening with its giant ghost in the dining room, the nigh-invincible skeleton and ghost enemies, the creepy-voiced flower pots in the churchyard and the creepy church with the disembodied ghost hand inside.
- Not to mention the well, which is on a raised area overlooking a pool of deadly water. Inside is, of course water, but in each direction is tentacles, forboding you from collecting all of the notes safely.
Rusty Bucket Bay. Water so toxic that it drowns you on the surface - that's two Primal Fears in one. And it isn't optional.
- Oh, and by the way... Snacker's back.
- The Grimlets in Rusty Bucket Bay are especially terrifying. They're basically metal pipes with huge fangs that lunge at Banjo and Kazooie when they get too near. They look like this in the actual game, but their beta design was even worse.
  - Don't forget, the Grimlets are disguised as regular pipes in which you go to to get certain items, the player more likely to first encounter a regular pipe before a Grimlet. They're virtually indistinguishable between the two...
The Zubbas nest in Click Clock Wood. If you're afraid of bees, keep away in spring. In the other seasons, it becomes Nightmare Retardant.
The zombified throne room in Tooie. Cheerful ally King Jingaling becomes zombified and attacks you, while his pet becomes reduced to nothing but ashes and a pair of eyes. All with horrifically depressing music.
In Tooie, Bottles's burnt corpse is lying in plain sight on Banjo's front lawn for the majority of the game.
Scrapped co-op game mode Bottles' Revenge, in which Banjo's best friend Bottles turns into a devil and is bent on getting revenge on Banjo for killing him ,even though the entire game was a quest to revive him, possessing his enemies so they could try to kill him.
The amount of Moral Dissonance involved with some of the bosses, especially in Tooie, can very well be this: most of said bosses are simply defending their territories, and the player is effectively just breaking into what is essentially their houses and killing them for shiny gold puzzle pieces. Lord Woo Fak Fak is the most jarring, as, basically, you're breaking into a blind old man's home trying to steal some shiny puzzle piece.
King Targitzan's Temple in Mayahem Temple is rather ominous, and a completely different type of play to all of the previous game. The dark corridors can make one nervous.
There's an area in the depths of Glitter Gulch Mine which is almost pitch-black, apart from a few generators. Also, one wrong step and you can be sent into the abyss.
- Old King Coal: not only does he literally look like an animated pile of burning coal, as the battle progresses, you shoot off both of his arms, and then his torso before finally defeating him, thus resulting in a big pair of disembodied burning coal legs running around the room while still alive. And the worst part is that he, of all bosses in the game, not only gets nicer after the battle, he also is the one boss that plays any role after the level is done, so you will keep being reminded of his scariness whenever you use the train.
Witchyworld is the typical Circus of Fear kind of level. In that respect, it's not particularly scary, in face the Cave of Horrors is the least unnerving part of the level. However, the way Mr Patch inflates himself is rather scary to some, even if the dialogue is rather humourous.
Jolly Roger's Lagoon had giant octopuses, huge puffer fish with equally big eyes who explode upon defeat via grenade egg, and electric eels thrown in for good measure.
- And the seaweed tends to give a lot of Paranoia Fuel, and surprise some in the same way the Grimlets do, albeit less terrifying.
- There's also a small area beside the town where two piglet kids wish to swim. The problem is that their little pool is badly polluted. So badly polluted that it caused one of the piglets to grow a third arm.
In Tooie, in Terrydactyland, one Jiggy involves you going inside a mountain and awakening a dinosaur who then eats you and asks you to shoot down a bunch of germs.
- Eels show up at Terrydactyland as well: at the top of the waterfall, players are welcomed by big-toothed and big-eyed eels.
- Stomponadon is introduced with a slow, ominous panning of what are called the "Stomping Grounds" while the boss intro music plays. Then a huge t-rex foot crashes down with a terrifying roar, out of nowhere.
The Mordor-like area outside the factory in Grunty Industries, especially considering the inside of said factory wasn't a whole lot better to begin with.
- The area outside the level, in the Isle o' Hags, the Quagmire is just as bad. Also, this is the first time you'll encounter a Minjo in an area which is somewhat out of reach, in other words, it's well disguised. It's from that point do Minjos recover their threat.
- The trash compactor in Grunty Industries is deafening and deadly.
The trope-naming original Hailfire Peaks has Fire and Ice dragons who randomly roar and send down fire balls and ice at you throughout the level. The only thing that makes up for it is the easiness of their Boss Battle.
The cyborg imposter posing as Mumbo attacks the players in Cloud Cuckooland; during the battle, the fake, Mumbo-like body parts fall off, only to be replaced by metallic creepiness. Plus, when you defeat him, his head falls off and he oozes green blood.
Gruntilda's Lair itself: aside from its Grunty-shaped entrance, the inside is dark, wall motifs are often intricate and weird, the music can be creepy at times, it contains spiderwebs, quite weird enemies and narcissistic pictures of Gruntilda, and before everything else, the entrances to the level areas have teeth and big glowing red eyes.
Minjos are evil robot Jinjos (little creatures you are trying to save) that are incredibly hard to kill once they attack you. There is absolutely no way to tell the difference between a Minjo and a Jinjo (unless you are able to fire a Grenade or Ice Egg at it) until you go over to it, and then, if it is a Minjo, it will charge at you and start growling creepily, while trying to electrocute you.
Cheato's theme song.