Unwanted Visitor

I have a story that freaked me out. It was around 12:30 in the morning and the house was quiet. I heard a funny noise that I thought was Jacob. I got up and went to check on him and as I came out of his room I heard Joe yell, "WHAT THE??" and a black cat ran out of our room with Joe chasing it. I have some news. We don't own a cat. Lovely. We have a stray cat running around in our house. And we have no idea how long it was in here. We are redoing our laundry room. It doesn't have a window right now and we left the cover off so it could air our and dry the dry wall mud and tape. It had been left open all. Day. This cat must have been chilling in our house for the afternoon. Luckily we haven't found any surprises! Talk about a heart attack!!