Thanks to Jim’s friend and Jeff at Nortel, I am confident that my creepy spider is indeed a spider that just happens to be missing a couple legs. It is a wolf spider, known for its ability to run really fast and jump really high (eeek!) My particular wolf spider was a mom; she was carrying a whole lot of young on her back (ewww).
As a bonus I give you the a page I found of absolutely horrifying close-up photographs of wolf spiders. Warning: not for the phobic. I had nightmares and I’m the one poking fast-running spiders to get better pictures of them.