Probably the best tale of reverse wiring transformers comes from the radio show of Art Bell.
Back in 1996, Art received a call from "Mad man Markum," and the story was confirmed by the man's probation officer. Simply put, "Markum" claimed to have made a time machine by stealing some PoCo transformers and setting them up on his front porch.
He succeeded in making a Jacob's ladder about 4-ft. across. When asked if he had 'tested' it for time travel, he said 'yes;' he had tossed some change into the arc. He said there was a very big flash and the coins disappeared. He was waiting for them to reappear, so he could 'calibrate' the device.
I think he will have a long wait.
A police visit to a neighbor led to the accidental discovery of his contraption, and his prosecution. Time served, he went to the PoCo and bought the transformers this time, and continued with his experiments.
I shudder to think of the voltage required to make an arc of that size. AFAIK, his neighbors haven't complained, and the NEC has no rules regarding such 'appliances.' I will admit that a 4-ft. arc does call into question the usual clearance rules
Over a period of years, I personally heard the many chats Art had with this man.