As a teenager, I once plugged a 9-pin VGA monitor into a 9-pin serial port. The computer turned on, did beeps and boops for a few seconds, and then white smoke

As a teenager, I once plugged a 9-pin VGA monitor into a 9-pin serial port. The computer turned on, did beeps and boops for a few seconds, and then white smoke started pouring out of the power supply. I quickly turned it off. After it cooled down; I connected it he monitor to the correct port and the computer fired up just fine.