Did I just kill my Arduino?

OK so from what I understand if you run the Arduino from a 12 volt power supply from the 2.1mm power plug there is no need to set a jumper on the board, correct?
I had two leads running out from the 5v and I think they touched just as I applied power. There was a snap and an arc. Now the board is dead.

No breakers to replace? Throw it away and buy a new one?

Almost all of us have done that at one time or another. Unless you are skilled at repairs, buying a new one is the safest approach.

After calming down a bit and doing some more reading about how nothing should have died from what happened… I plugged the USB cable in and checked it out. The microcontroller still runs the last sketch uploaded to it. Just blew the regulator from the 2.1mm jack I guess.