I did the same thing! We built an Isuzu pickup with six Cerwin Vega Stroker 12's and six custom, one off linear power 2500 watt monoblock amps. I can't remember how many yellow tops we had in there but we used 1" X 1" aluminum bar for the buss bars and after tightening the last battery, the wrench slipped out of my hand. It instantly vaporized in the middle and I swatted the molten metal off of the top of the battery before it did any damage. We had to bolt a chunk of 2" x 4" solid aluminum from between the seats to the top middle of the windshield frame to keep the 3/4" lexan windshield from blowing it's rivets out! That truck was hitting 174.9db......in 1996!
The most recent battery short was while demonstrating the coolness of my lipo parallel blocks to someone. As I was saying, "I designed these so that the batteries can only be plugged in correctly.", I touched the lipo bullets to the parallel block in reverse polarity causing a giant spark and the instantaneous vaporization of the two 75A castle bullets that connected the pack to the controller. My ego has a scar from that one...didn't burn my fingers though! While it was impossible to actually plug the battery packs in backwards, it sure wasn't impossible to touch the terminals together!