Must have hooked up to the wrong terminals.
I was driving one night through south central California, when my electrical system started to fail.
I came to a stop by this big lake.
I happened to have a jumper cable and a couple of electrodes with me, so I hooked one end up to my battery and dropped the other end into the lake.
Before you know it, the CHP came by, and I was charged with a Salton battery.