It's a Wolf Spider. Don't listen to anyone else. It's harmless but, like all spiders, it can bite so I would kill it.
That's what I thought, a wolf spider.
That was my first thought, since we had a wolf spider in our house in California a couple of years ago, but this one seemed to be making a nest/web out of dust bunnies under there, so I wasn't sure. I thought they only did their hunting outside.
Oh, and the weather has been super mild here, so the cold didn't drive it in, I don't think.