- The Castle/Fortress Theme which creates an effective atmosphere for the level's boss fight. Some castle/fortress levels have a passageway between the red doors and the boss fight, with this eerie music setting the tone.
- 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 Toadies catch him and fly away with him. To make matters worse, some enemies will attempt to take Baby Mario when he's in the air or just plainly swipe him off Yoshi's saddle. The accompanying sound effect doesn't make things any better.
- Neglecting to retrieve Baby Mario in time rewards you with an image that consists of the Toadies carrying Baby Mario away against a black background, with one of them snickering at you before they take off. The noise they make doesn't help.
- The motif that plays whenever Yoshi gets an instant death (e.g., falling into a bottomless pit, touching a thorn, landing on spikes). When this happens, the screen transitions to black through a swift horizontal zig-zag wipe effect. It is really unsettling, and the high-pitched version featured in the enhanced GBA port is no better.
- The "Game Over" screen 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.
- 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 Yoshi whole, as will the giant catfish lurking in the waters of several jungle levels. There are also a few chase scenes in which a gigantic Chain Chomp is out to eat Yoshi (and the very ground you stand on).
- Kamek would enlarge small creatures in the boss battles. The transformations were complete with music that suggested "time to die".
- The falling walls in Burt's fort which will crush Yoshi if he's underneath one.
- The tiny Chain Chomp in the background of a room in Sluggy's fort that becomes huge and bites at the screen.
- Sluggy the Unshaven is one of the scariest bosses in the game. It makes it even scarier when you have to aim at his heart to defeat him. It's almost surprising that he's a mid-world boss.
- Bigger Boo gets larger as you throw eggs at him until he explodes.
- Naval Piranha is terrifying if you imagine a giant monster plant that charges at you, and the boss itself is referencing Little Shop of Horrors. The fact that a Yoshi game is referencing a theatre play like that can be really unsettling.
- When you defeat Tap-Tap the Red Nose, he falls into a pool of lava and you watch him helplessly try to swim out before sinking. Of course, that's nothing compared to Tap-Tap the Golden in Bowser's Castle.
- The titular Fuzzies in World 1-7, "Touch Fuzzy, Get Dizzy", assuming you aren't giggling from Yoshi getting high off his ass. Touch or eat one, and watch as the world begins to wobble and warp in front of your eyes while Yoshi staggers around and the music distorts. It's worse when they reappear in Worlds 4-1 and 6-3, where they appear over large chasms, so if you touch one, you may very well stagger off the edge and towards your doom.
- 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...
- While nearly every boss suffers a quick death, Prince Froggy is defeated from his stomach. The background of his stomach slowly turns red as he gets more and more close to being defeated, and when you do defeat him, after you, ahem, leave his body through the back, Prince Froggy is spasming on the ground. All in all, one could argue that Froggy slowly dies from bleeding internally. Yoshi's face when you defeat him says it all.
- The sound of the Lunge Fish is one of the most terrifying sounds in video games. The Lunge Fish just comes right out of nowhere and eats you, killing you instantly.
- Incoming Chomps, which are giant Chain Chomps that fall from the sky. Not only the fear of getting hit and falling into the holes they leave, but those faces. And these things are found in the second level of the game! Even more unsettling is the fact that they start off in the background, just bouncing around minding their business. Then you cross their field of view and suddenly turn to face you and leap towards the foreground. One can only imagine little kids playing this stage and getting scared.
- 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.
- The chalk drawings suddenly coming to life during the train sections of the game. Especially if you're playing it for the first time as they look like harmless background scribbles.
- The Dizzy Dandy. If you're not paying attention to them (the real ones smile, the fakes have an evil smirk on them) you'll run right into them as they suddenly drop down and roll after you.
- The Slimes, which just fall into Uncanny Valley. They disguise themselves as block-looking platforms until you touch them, which makes them transform. The worst part is that not all of the block-like platforms are Slimes, making it hard to predict which one is a Slime or not.
- World 6. The first five worlds in the game all have some sort of charming quality to them for the most part: Smiling flowers, adorable-looking fauna and lush-looking backgrounds. Then you find yourself in the hellish wasteland that is World 6. The ground is brown and dead, all the forest's trees have been petrified, bones and Skeleton Goonies litter the landscape and lava flows freely in nearly every level. This raises an interesting question — just where is World 6, anyway?
- The final level is full of it:
- 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, an invincible golden version of Tap-Tap the Red Nose, is chasing Yoshi across a rocky, lava-filled area, as the screen ever so slowly autoscrolls 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, as shown in the image above. 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. 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. Also, in the SNES version, the boss theme plays during this chase. But in the GBA version, the music that plays is when you're about to encounter a boss, which just makes it worse.
- Before the final battle is another chase scene, only this one is an Auto-Scrolling 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 hardcore heavy metal music, a jarring contrast to the other music in the game, 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 is that 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. And when he does... His design◊ note certainly doesn't help matters. At least his first form was downright Ugly Cute (and arguably even a Designated Villain at worst).
- "The Impossible? Maze" is one of the extra levels in Yoshi's Island, and is quite possibly one of the eeriest levels in the game. As the name suggests, it's a dark labyrinth that is seemingly endless until you know exactly what to do. It's also one of the very few levels to feature Grim Leechers, which are enemies that latch onto you and reverse your controls. And if that's not bad enough, the soundtrack that plays in this level in the "Room Before Boss" theme.
- Aside from in-game fuel, there's a commercial for the SNES game where some guy in a restaurant tries to eat as much as Yoshi... and just like Mr. Creosote, the guy explodes, splattering everyone with his stomach contents (thankfully, this version of the ad only aired a few times, before being swiftly pulled and replaced with a censored version in which the splattering and exploding happens off-screen as a woman in the restaurant turns and looks to the left, and then the stomach contents spelling out "PLAY IT LOUD" are now a rich, thin, bright, non-disgusting green slime that resembles Nickelodeon slime).
Nightmare Fuel / Yoshi's Island
Don't be fooled by its cutesy appearance. Yoshi's Island has many frightening elements.