Many, many years ago a buddy and I were pulling the head off his Alfa Romeo sedan. The project started just to be replacing the cam cover gasket, but not all went well so the head needed to come off.
As darkness fell on us and it had been a very long flustering day, I was turning a wrench to remove an exhaust stud nut. All of a sudden, sparks flew and the wrench got real hot real quick, and we both jumped away. I looked at him and said “I found your starter” we both just stopped and laughed some tension away. We had not disconnected the battery since it was supposed to be just a cam cover gasket replacement.