This one ended kind of funny, but here goes:

When I was about 7 or 8, I was laying in bed trying to sleep through a brutal thunder storm. I was the only person sleeping on the second story of a 150 year old farmhouse. The house creaked and settled and was thoroughly terrifying to me as a child, so much that I usually slept with the lights on. I just knew there were legions of ghosts and monsters ready to attack me. So this thunder storm wasn't doing anything for my nerves. I finally got to sleep, but was awakened by deafening thunder. I looked up to see the wall near the foot of my bed with blood streaming down it. All the nightmares were coming true. The problem was, I wasn't allowed to leave my bedroom. My parents had gotten tired of hearing that I was scared. So I laid there all night watching the blood drip down from the ceiling. Paralyzed with fear.

Finally morning came and I went barreling out of the room to get my parents. I pictured one of those moments like in IT where only I can see the blood, but no, my parents could see it too. It turns out that after 100 or so years, the dark red bricks of the chimney were dissolving and the dust from them formed a sludge in the rain!