Nightmare Fuel / Pokemon Opalo

• Céfirean Ariados. Freaking Céfirean Ariados and the human-shaped wrapped prey it carries around. In Indigo Forest, Mundanez gets caught and bound in webbing by a swarm of Spinaraks and Ariados. After you defeat them and he calls for you to free him, you rip open the wrong "parcel", and there's a skeleton inside.
• Caligine Prison has Dusknoirs patrolling the halls, draining the inmates' willpower and sanity, Dementor style. It's treated as the torture form it is, and much later on, you find out Zalea's son got locked in there for a minor crime. He ended up so psychologically broken he no longer recognised her.
• You've just become Champion, Apolo and Vera have gotten married, and you, they and Mundanez are on the way to West Céfira. The mood is buoyant, until out of nowhere, a mysterious group attacks. They blow up the truck, and the aftermath is horrific - it isn't even clear at first whether Vera and Mundanez are still alive (thankfully it later turns out they are, albeit with permanent injuries), and one side of Apolo's face is a bloodied mess.
• The zombies in the voodoo salon are still semi-conscious, and aware that their bodies and minds are being controlled.
• The literal eldritch horror of a Pokemon, Unktena. Since becoming corrupted, it's ravaged the universe by devouring entire worlds, and it's heading towards Earth. Its influence takes a major toll on people's sanity, it's far more powerful than even the Great Spirit, and it's huge - when Zalea summons it, you see it towering over the planet.