So, what's that big ugly thing I just killed?  Someone said it was a vinegaroon, vinegarette,,,,,whatever.  It's really ugly. 

Most likely it is a wind spider.  Really large, travel fast for their size, look like a scorpion without pincers or a tail.  Big ugly red mandables.  Yep, that's it! 

They're a non venom critter in the arachniad family.  First line of defense is intimidation.  If scared, they will run toward you waving their clubbed front legs at you or their attacker.  If they bite you, it may raise a welt.  Again no venom, just bacteria from the ground.