Huge bug in my basement.

So my basement flooded like 2 weeks ago, and our insurance company came and took all our flooring and stuff. So right now our basement just has the cement showing. So yesterday we get back home from grocery shopping, and my mom says to me, "oh, they left the stuff here. Use it please." By "stuff" she meant the tarps. And that's the only thing I knew about. Anyways, I start laying down the tarps around the corner right by the stairs to the basement, and right as I lay it down, I see this huge bug scurrying along on the ground. It was black, and I could only see its body, but I swear it was around 8 inches long! I sceamed up the stairs for my mom and dad to come see what it was. My dad sceamed and said, "It must have been left here by the insurance people." And my mom was like, "No, it must have been living in the flooring." And I was like, "I don't care who's sceaming louder! I sceamed first up the stairs, you didn't."