Bug fossil

I was vacuuming our new house for the first time last weekend (shush) and near the front door there was a black blob that I first thought was a ball of fuzz. I quickly realized it wasn't when the thing wasn't being sucked up. So I looked closer, and was quite puzzled by what I saw:



It first to appeared to be a very flattened fly, but then I blew at it and it didn't go anywhere. I tentatively scratched at it with my fingernail and found it to be part of the floor. It's very intriguing, this fossil/imprint/impression of a fly that happens to be in our floorboards. It evens has a white-ish area (to the top right in the photo, under one of the legs) that could be a wing. I wonder how the fly got there. It's almost as neat as a bug in amber...