It's called Steatoda grossa or a False Black Widow.
I turned everything upside down and vacuumed every nook and cranny. I get the creeps every time I think about it crawling around in that bedroom. It was only about a half inch long, but a look at that bulbous posterior sure made me jump back three feet. I couldn't find too much information on Google, but I was able to quickly find a photo and the name for this menacing creature. Females could live up to six years!
I'm ending this post because I'm getting the willies every time I look at the photo. I usually like looking at photos of spiders and insects, but when it's one that was inside my home and in a bedroom...well it isn't as fun to look at.
Check out Bug Sufari. She does a beautiful job of photographing spiders and all sorts of insects.