While exploring with my best friend, we stumbled upon something that's really bothering me. I was walking over a sewage tunnel (large enough for me to crawl through) and tripped, only to look down and see black splotches on the cement. Wet. Glistening. Pure black. Like something you'd see in a scary movie. Anyways, I look right above it, and above it there is a hole with something weird in it and a bunch of the black goo surrounding it. What could this goo be? I'm super freaked.