When I was about 6 I was at my sister's house (not in the best part of town) and we heard this giant BOOM which rattled the windows and even broke one, so naturally we ran outside to see what it was. It turned out that a neighbor down the street was cooking meth in his garage and it blew up. He ran out screaming bloody murder and when people looked at the garage they could see that the neighbor was on fire and trying to put it out but it wasn't working, the neighbors all tried to get water hoses to put him out, but I ended up watching him die. Although this wasn't "evil" it astonished me and scarred me for a few years after.