Spoilers, obviously.
Let's try and make a list of stuff that changes in the game either just to mess with your head, or when your sanity is lower.
Here's the stuff I remember:
- Body in the Transept, in one of the hanging cages appears and disappears
- Painting in the Transept of Alexander turns into the same painting with a horrible disfigured face
- Painted bodies hang from the ceiling in the choir entrance with low sanity
- The rocks in the wine cellar are first sealed shut, then later appear smashed open
- Water monster apparition in the Sewers
What else can you guys remember?