I Have A Vision is a 2 page storytelling trpg about an architect who has become fixated on a particular creation.
As a group, you play the architect and the people / visions surrounding them.
As a group, you also draw the creation piece by piece.
Vision is not explicitly a horror game, but I can definitely see it having that function. If you wanted a prelude to a Delta Green scenario, you could accomplish that with a round of this. Alternately, your architect's creation can be positive or tragic or merely strange, and the game's story can be confined to just a one-shot.
The rules and structure of Vision are a little loose, but that didn't feel like a bad thing. It simply gives the group a lot of leeway to decide what the tone of their story is going to be.
Overall, I would recommend this to any group that feels comfortable telling a story, and that is willing to take a broad pitch and run with it as far as they can in their own direction.