A Yablochkov candle was an early kind of arc light, consisting of a strip of plaster with two carbon rods running along its edges and shorted together with a fuse wire at one end. By connecting line voltage to the other end of the carbon rods, you vaporize the fuse wire, initiating an arc, which then continues between the ends of the carbon electrodes, burning down the rods and the plaster at the same speed. Later models included some metal powder in the plaster so you could initiate it a second time.
It occurred to me that if you had a hole through the center of the plaster, you could blow air through it to squirt some of the plasma onto things, thus perhaps cutting them; this gives you a plasma cutter suitable for non-metals. And with a modern constant-current supply (or even a ghetto version consisting of a quartz-halogen lightbulb or ten in series with the carbon rods and a voltage source high enough to strike the arc) you maybe don’t even need the fuse wire.