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Subjects of Equestria! We are pleased to kick off the Nightmare Night Festivities and the 14th anniversary of the return of our beloved Princess Luna! Join us in celebration!
Yeah, I was going to say that too, but remove the sparks and it does sort of look like an old vacuum tube diode.
Though, yes, it’s probably a Jacob’s Ladder.
It’s throwing sparks, so I assume it’s a device called a ‘Jacob’s Ladder’ that uses high voltage to throw an arc between the rods and the rods are normally angled apart slightly so the arc travels upwards, disappears and then reappears at the bottom to repeat the process. They were commonly used as props in Frankenstein-type monster movies.
I was about to tell you that’s not a diode, but apparently there are vacuum tube based diodes that look sort of like that.