Bioshock (spoiler alert):
There is this part where you go inside a secret cellar to find a "power to the people" machine (it allows you to upgrade one weapon). It is very dark and the cellar is flooded, there is water dripping from the ceiling. As you walk down the stairs the first thing you will see is a "Splicer" (Crazed addict), sitting on a chair facing an corner of the cellar. The splicer is entirely white because the splicer is covered in some sort of concrete, making it a statue (in this level there are several statues like this). When you walk down the stairs you will see a long flooded hallway, at the end there is the "power to the people" machine. As you walk near it the lights start to flicker and you hear something laugh behind you, when you look back at the stairs everything is still the same, you can see the statue is still sitting in its chair facing the corner. Then you use the machine and turn around to make your way back to the stairs, only to see a statue right behind you, and the chair is now empty, it doesn't move for five seconds but after that it attacks you, this really scared the shit out of me.
