I was a theater projectionist, back when you had 20 minute reels you had to constantly change, while babysitting two high-voltage, water-cooled, carbon arc projectors. Sometimes the film would break and you’d have to splice it. So when the theater got a print in, you had to count and log the number of splices for each reel, then the next theater would do the same and retire the print when it got too spliced up (plus, sometimes if it was the last night of a run, some lazy projectionists would splice it in place with masking tape and then you’d have to fix it). Sometimes you had to splice in new trailers or remove inappropriate ones as well.
Anyway, you counted splices by rapidly winding through the reel with a benchtop motor with a speed control belted to a takeup reel while the source spun freely. Then, while letting the film slide between your fingers, counting each “bump” you felt as it wound through. I was told to ground myself by touching the metal switch plate of the speed control knob with my other hand. One night I forgot and let go until my hair started rising. I’d gone through most of the reel at a very high speed and acquired its charge.
I reached for the switch plate and shot an 8-10” arcing discharge between the plate and my fingers.
Lesson learned, I held the switch plate from then on.