Spider identification: male black widow?
I think it's unlikely.  Without a photo, it's hard to be sure of anything, but Black Widows don't have reddish legs or enlarged fangs, and it's hard to think of any circumstances in which they could be called "very quick".
Your description might fit a spider called Dysdera crocata (here's a link: https://bugguide.net/node/view/3388 ), but that's purely a guess on my part.
The problem with trying to ID something from photos when you're not very familiar with it, is that you may not be sure what to look at to distinguish it.  If you can't get a photo, make sure you include the most detailed possible description, including anything about it, no matter how seemingly insignificant.  What it was doing, where it was, etc., etc.