Nightmare Fuel: Sonic Adventure 2

  • Gerald Robotnik's speech. With the voices set to Japanese, he talks in a Creepy Monotone. In English, he sounds like he's going even more insane.
    • The image of Gerald Robotnik tied in chains and facing the camera in the video that's sent out to the entire world creeped a lot of kids out back in the day. It was just something you never thought you would see in a Sonic game.
    • Gerald's diary isn't a basket of roses either, describing his descent into madness from his grief over losing Maria. First he seems confused and sad, then scared, a vicious, hateful growl, and finally when outlining his intentions for Shadow, he seems eerily calm, almost cheerful in his annunciations, as if giddy in his belief that his actions will lead to the end of the world.
    Prof. Gerald: Based on my original projections, I completed my project, Shadow... I designed its mind to be perfect, pure. I will leave everything to him~.
  • The trailer for the Last Story.
    Rouge: The end of the world...
  • The scene with Eggman's demonstration of the Eclipse Cannon was full of this. Arguably, the scariest part wasn't watching the laser pass close by the skyscrapers and blowing a large chunk out of the moon, but the timer seen at the end as Eggman laughs.
  • The boos from the haunted stages such as Pumpkin Hill and Death Chamber have yellow eyes and creepy grins, and they will pop up unexpectedly at you. They can be well-hidden behind walls, floors, objects, and even in their smaller forms.
  • King Boom Boo, who even scares Knuckles.
  • Eggman's threats if you take too long on Crazy Gadget are surprisingly harsh, and he holds a gun to Amy's head in the cutscene following the level.
    Eggman: Sonic, if you don't come here, she will die!
  • Sonic comes the closest to death he's ever been when Eggman traps him in a self-destructing capsule. If you play the Dark Story first, there is no indication that he survived.
    • Eggman's recap on the following boss fight is even worse.
    Eggman: Hahahahahaha! I finally did it! I've defeated Sonic! That annoying hedgehog is now gone forever! He's nothing but floating chunks in space now!
  • Egg Quarters. Not because of the ghosts, but those Beetle robots. You never know where they are unless one of them is in the same room as you, and turning a corner to suddenly see one in your face can be quite scary!