Yes, unfortunately the "wrench-battery-arc-welder-syndrome" is an all too common occurrence. When I was a kid I worked at a hot-rod shop and one of the other mechanics there dropped a wrench which shorted between a pos. battery terminal and the vehicle's frame. The wrench welded itself in place and
glowed orange before he was able to grab another tool to knock it off. It scared the heck out him… and me too!
To prevent this I have battery disconnects and have also installed fuses directly to each of my (+) battery terminals.

As an additional (and inexpensive) preventive measure when working on my electrical system, I always wrap the handles of my
open end wrenches (and/or screwdrivers) with
Rescue Tape.
Glad to hear that the only damage was to your ego ;)
Cheers
-Mark