Please don't list this on a work's page as a trope. Examples can go on the work's YMMV tab.
Nightmare Fuel: Fire Emblem Awakening
Grima and the Bad Future in general. In a flashback, even Lucina, who is a Badass and mostly fearless young lady, lets out a blood-chilling scream at the sight of the monster. All the reports you hear about the Bad Future are no better.
Robin even points out how creepy this is in their C-Support. And then there's Tharja's confession scene to a male Robin, where she threatens to kill him should he ever back out of the relationship.
Take Henry with you during the Death's Embrace DLC map. It's Nightmare Fuel on its own for differentreasons, but you know that horrible floor that shoots sharp spikes to impale your party and always reduce your HP to One? Every turn? Yeah. Henry mentions that the room is just like one that he was sent to during school as "punishment." Is it any wonder he's so unhinged?
Henry: The spikes here remind me of the ones back in wizard school. Whenever I did something naughty, they'd put me in a room like this. ...I almost died! It was neat. Still, nonstop pain is no fun for anyone, so I'll try to make this quick!
The special "entombed" risen. The other risen are just  of Generic classes. The entombed, on the other hand, are unique little freaks that wear bag...things on their heads, sink in the ground and attack you with their bare hands. Oh, and their head twitches all over the god damn place. The fact that they're basically weak metal slimes does little to comfort.