It could be a silverfish... They are pretty fast but they are typically a brownish grayish color but I have seen some really dark brown ones that were pretty much black.
just open the window or the door and let it go out, you could also try getting some pest repellers, they help a lot, you wont hardly see any bugs
Can you put a picture? You could use two cups to catch it also. Use one to scoot it into the other, then use the one without the bug as a lid. Put it outside. :o)
try google it also
Last night, there was a kind of big, black bug on my wall. It was an inch or two long. After I saw it, it started moving but it moved incredibly fast. It hid under a bag so then I ran out and slept on my couch. This morning, as I was cleaning my room, I lifted up a box and saw it moving around and it wasn't any slower. I tried looking up what bug it was and it's not a mouse, ground beetle, or American cockroach. It looked like it had 6-10 legs but I couldn't tell. If you could help me identify it and tell me how I could get rid of it, then that would be greatly appreciated.
