When I was in high school (late 60s), a friend made a Jacob's ladder using the transformer from an X-ray unit that was used in shoe stores (many years before) to check for foot bone problems caused by ill fitting shoes.
Imagine working around that all day, selling shoes.
The transformer was as big as a breadbox, and made a very thick, noisy, turbulent arc that easily started at 6" and walked up to points at the top of the ladder about 14" apart, where it died with a pop. I had no desire to play with it, ever. No, no, no.