- The first game:
- The ghosts; if you touch them, they turn into a crazy vortex and chase you everywhere, with a constant demonic groaning noise, and the screen shaking. It doesn't always happen immediately either.
- Reading "De Vermis Mysteriis" while standing outside the marked tile causes your character to utter a horrified moan as an unseen force lifts them up, and then very quickly and with no warning snaps their spine in half and hurls their body back to the ground.
- If you get clever and simply try to walk out the front doors before you're allowed to, you get sucked into the Great Old One waiting right outside.
- The third game:
- The recording of the ghost killing the actor is a lot more unsettling than most of the series' monsters, and its different art style helps it feel otherworldly.
- The New Nightmare:
- The Giant Space Flea from Nowhere Mini-Boss in the library.
- You are walking along hoping that you don't get attacked by another dog, when all of a sudden you hear a scream and when you walk toward the source, you hear a splash and then the game goes quiet for a second.
- Before entering the mansion, there's a chance that you might encounter a group of ghosts that show up during lightning strikes.
- Similarly, you can encounter more of them in a random office in the mansion, but the thing is unlike the ones at the gate, you ''don't'' go back and fight them, they're just there for the scare.
- The 2008 reboot:Lucifer: Did you think I'd come alone?
Nightmare Fuel / Alone in the Dark