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I was never a believer until this happened to me, and this is a completely true story. I was over a friend's house for a party. She lives in a big old house, which was built during just before the civil war. Everyone was upstairs in the attic when the doorbell rang. Megs (my friend) looked out the window, and saw that it was the pizza guy, so everyone went down stairs. Megs turned off the radio and TV before we went down. I went with them.
When I got downstairs, we realized we'd left the cups for the soda upstairs in the attic, so I went up to get them. As I got to the landing on the third floor, I felt a deep chill, and got goosebumps on my arms and neck. I went up the spiral staircase to the attic with the weirdest feeling that someone was following me. When I got back into the attic, everything was as we had left it. However, as I went to cross the room to get the cups, the TV and radio turned on. This scared me a lot. The TV was turning weird colrs. It started at purple, and then went to a weird greenish hue. I grabbed the cups, and bombed it down the stairs. I wanted to get the hell out of that room as soon as possible.
I didn't want to look like a mess in front of everyone, so I didn't mention it until I could say it discreetly to Megs. I asked her something to the effect of "Is your house haunted, by any chance?" (Yeah, I felt pretty smooth right then.) It turned out that her house was haunted. Apparently (and this is the story she tells me) her house was part of the Underground Railroad, but one day several slaves were caught in the basement, and two of them struggled and were killed. I don't know if that story is true or not, but I do know that some not-normal stuff happened that night, and that's about all there is to it.