Idea of story from dream.

My dream was about a horror story which can turn into a fairly good fimfiction. It would start as twilight sparkle going to rarity's place, they would talk about anything but then twilight takes a interest to a door (which rarity says going to the basement.), twilight would want to go down that but rarity would try to delay her, it would of course fail. Twilight goes down and opens the door to a slaughter room. And while rarity is trying to explain, twilight would have a smile on her face. She would say that it's fine and that rarity doesn't have to worry. Rarity would take it that means that they can leave...twilight locks the door. Twilight then asks if she can see how rarity did it....how rarity killed spike....all with a smile. Then rarity (worried that twilight is very pissed and it would be wise to not angry her any more then she already is, decides to describe how she did it. After each explanation, twilight would give a fact about something horrible and then say that "i had been reading a lot about stuff like that. you know, after spike's death."
I would explain the dream more but it actually ended around there, but i guess you can guess where it would end.