The Hitman series is brutal, as you would expect from a franchise where you play a hired killer, but it's not a frightening game. The third entry focuses on stealth when it comes to completing your missions, but if you stray just a bit off the beaten path there are a couple of deeply unsettling little paranormal pockets.
The first is in the Meat King's Party mission. An obese criminal called the Meat King is celebrating a court case against him collapsing, and Agent 47 infiltrates it to kill him and hopefully rescue the daughter of his employer. She's unfortunately dead and partially butchered. If you shoot the record player in the room where you find her, then turn the volume way up on your TV, you can hear eerie feminine laughter that comes from nowhere.
More well-known is the ghost in the Traditions of the Trade mission, where you are out to eliminate a terrorist and retrieve a chemical bomb. It takes place in the Thermal Bath Hotel, and by picking the lock to a closed wing you can stumble across a murder scene that includes a knife stuck in a wall and a bathtub full of blood. If you happen to look in the mirror of the bathroom a ghost suddenly appears behind you. Is he there when you turn around? Did you flunk Horror Movie 101?
Remember, this isn't part of the plot. You get nothing for finding the ghost... except a need to change your pants. It's just there. Waiting.