- When Aerial first beckons Chise to come to the land of fae, there is a very sinister shot of all of the fairies, complete with Glowing Eyes of Doom and The Darkness Gazes Back, pictured above. As Chise uses her willpower to resist, she's gripping her arm so tightly that her nails are cutting into her skin.
- The creature that chases Chise while she's exploring the cemetery and who would clearly have killed her if it wasn't for Ulysses' intervention. The anime makes it all the more terrifying.
- Elias's past is as mysterious as it is unnerving: Lindel found him in forest, where his earliest memory was just walking. Since they had no idea what he was, Lindel took him to Rahab, his master, and even she had no idea. He then says all he remembered before walking was: red.
- A mob chased Lindel after a little girl was able to see Elias. After one managed to hit Lindel and seriously injure him with a rock, Elias emerges from his shadow and attacks the mob, and given what he says to Lindel afterwards, if it wasn't for Lindel pulling a Teleportation spell, he would have done worse than just attack them.
- Elias in general can be nightmarish at times. His relationship with Chise is sweet enough that it can be easy to forget that he's a Humanoid Abomination that doesn't think like a human, and initially only bought her as a curiosity. His Becoming the Mask sometimes creates even more problems, because as Elias gets wracked by emotions he had never felt before, doesn't understand and has no idea how to deal with, he can lash out in unpredictable ways. Even Chise is not always entirely safe from him. As for anyone who is not Chise, well... Elias may not be overtly hostile, but if for whatever reason you stand between him and his objectives, don't think for a single second he has anything even close to human morality to hold him back.
- Whatever the heck comes out of Renfreds book in Alices flashback in episode 16: imagine you just open up a random book, only for a monster with a giant eyeball and two mouths and sharp claws jumps out to attack you.
- The aftermath of Chise trying to Mana Drain a dragon. When Elias and co. rescue her, they pull out Chise... and whatever the heck this is.
- It's later revealed to be a dragon's curse, which not only morphs her arm into a a grotesque claw, but also cuts into her already meager life expectancy as a Sleigh Beggy to less than a year.
- The black slimey...thing with teeth that is implied to consistently show up and eat Chise's food when she was a kid, and it would do so at daylight.
- Episode 17 of the anime has a few alarming moments:
- When Stella asks for Chise's help in finding her brother, Elias takes temporary control of Chise's body to demand payment for their services. Her face goes blank, her voice drops, her intonation goes flat, her eyes turn silver, and prehensile inky black shadows creep up her neck. Did we mention Elias is demanding payment for helping a distraught pre-teen girl find her brother? It's a prime example of his Blue and Orange Morality. Granted, he settles for sweets almost immediately, but still.
- While hunting for Ethan through the forest, Chise runs out of crystal flowers to pay the neighbors with for their help. She uncovers her arm, instructs the fey creature "No more than half a teacup's worth," and allows it to chomp its gnarled teeth directly into her arm to drain her blood. It's even worse for Stella, who can't even see what Chise is talking to or why she spontaneously starts gushing blood.
- Elias laps up the leftover blood on her arm with his long tongue, a chilling reminder of his inhuman nature.
- The entire premise, as unfurled by Ashen Eye, who's behind the day's events: A little girl, in a fit of frustration, snaps at her younger brother for a trivial slight and tells him that she doesn't need him. A fey being nearby takes her at her word and abducts the brother for his own unspoken reasons, causing him to slowly be Ret Gone from his family's memories.
- Joseph/Cartaphilus is a very messed up individual, but there's a good chance he didn't get that way for no reason. It's made abundantly clear his endless life is a curse, not a blessing. His body is constantly falling apart and the process apparently causes him immense pain. His limbs occasionally just fall off and turn into a wretched purple sludge. In at least one close-up, you can see an exposed bone in his rotting finger, and that's probably only the early stages of the deterioration. At the same time, he is immortal, so it's entirely possible that if he were to fall apart completely, that would not end his suffering, but just leave him an inert, yet fully conscious pile of sludge. Forever.
Nightmare Fuel / The Ancient Magus' Bride