Horror is interesting because it and tragedy are an exception to many of the standard statements about the purpose of writing and how to satisfy the reader.

In addition to the types above, there''re also the types of horror where the horriffic thing is inside the main character''s mind (you suspect that the world is sane but you are percieving it in a crazy/drugged/hacked VR way), or inside the main character''s body (alien egg gets implanted in you and will hatch and the hatchling(s) will eat you/take over your mind), or what I think of as silent horror: where there''s something like the extinction of a race happening on a huge scale, but it''s either happening so slowly or the immediate benefits seem to outweigh the long term horror, so the characters in the book go merrily along and only the reader and the narrator feel the horror.

So what are the feelings that add up to horror? Fear of course, and helplessness, pity, disgust... help me out here. What does the writer of a horror story or game want the reader to feel in order to satisfy them.