- The Cave of Bad Dreams. The cave itself is made from nightmarishly grotesque faces, for most of the level, you're riding on skulls across what's pretty much the river Styx. Next you have these wooden claw-like things that sweep out at intervals on the wall, if you get caught by one, it slams Rayman around before dragging him into its hole, where he loses some health and respawns. Next up, we get the mini-guardians, these things aren't much of a threat on their own, but if they get close enough to Rayman, they'll swallow him whole and alive for hp loss and a respawn. At the very end of the cave, the Guardian arrives and attempts to eat Rayman, the camera switches to Shaky P.O.V. Cam of his mouth as you attempt to escape him on a slide.
- The Tomb of the Ancients. There are skeletons everywhere, the wall design is very similar to the Cave of Bad Dreams, and it has another river Styx boat ride This time you have to fend off zombie chickens on a very small barrel; once you get to the end of that area, you find a pitfall. The tempo of the music changes to Psycho Strings after you get down to the bottom, at a tempo played to simulate something skittering towards you from the darkness, right before a Giant Spider attacks you. The music.
- Most of The Desert Of The Knaaren from the third game. The top is eyebrow-raising enough, with a land of lava and acid pools, but once you fall underground OHHH BOY. It's not just the fact that the place is completely dark and filled with skulls. The Teensies warn you that the Knareen are invincible, they are not joking. The Knareen are the scariest enemies in the entire series, being COMPLETELY INVINCIBLE and forcing you to sneak past them, being shrouded in hoods and having strange inhuman growls, and constantly screaming to devour Rayman.
- It certainly doesn't help that this is the only level that the zombie chickens show up in this game, often in a place where your hands are busy with carrying an egg across the room where they show up in. Granted, you can put it down, but that doesn't make the fact that these zombie chickens glow eerily, that they come in packs of three or four, and this music plays when they're not there (and THIS music plays when they are). Your nerves would already be in shreds after having to deal with Knaaren, and this one keeps hacking at them.
- Most of "Swimming with Stars" in Rayman Origins since it's the first level that isn't whimsical and cheery like everything else up to that point. If the creepy enemies didn't get you, then the oppressive darkness and haunting music will.
- Also, the music of the swimming levels in general. For the most part, it's ridiculously cheerful. However, for one reason or another, the creator of the music apparently thought that it would be a good idea to include what sounds like one of the singers drowning while singing. And try to play it for laughs, even.
- Some of The Magician's comments when you bop his top hat foreshadow his villainous qualities, or at least that he's not nearly as nice as other characters.
- The level "This Heartburn's for You" in Rayman Origins. You get eaten by a dragon, and you're inside its body. The music is humorous and catchy, but that doesn't change the fact that when you reach the stomach, you can see the dragon's realistic looking heart through its apparently transparent stomach. And then you have to pop the growths inside the dragon, which are apparently what mutated it in the first place. Which means that the dragon has mutated and become enormous due to growths that could only be destroyed by entering its body and attacking on the inside while avoiding its stomach acid and flames.
- The boss of Olympus Maximus in Rayman Legends. It's a giant floating cloud of the Dark Creatures from previous levels, which shape into the form of a giant hand, two flying demons, and then a giant floating demon. The music is also very dark and low key, unlike most of the music in the game. It's just too bad that it's a very easy boss.
Nightmare Fuel / Rayman
Rayman has several examples of Nightmare Fuel, notably most of them in the second game.