This is a Jacob's ladder doing its thing. I made it with two stiff pieces of 10AWG bare copper wire attached directly to the output bushings of aTransco 15KV/30ma NST. It was easy to build and required only a few minutes of fiddling to get satisfactory performance. The wires get scorching hot after a few minutes.
I'm often asked if a car ignition coil can power a Jacob's ladder. Well, the answer is yes, it can. High voltage experimenter Tony Giovanni sent me this excellent digital photo of a small ladder powered by a car ignition coil. His setup is a 4uF cap and a 240vac/50Hz solid-state dimmer switch. Cool picture Tony, thanks. You can visit Tony's web site at:http://x0.na.nu:3000/
If you want to build something cool but lack the skills or confidence to tackle a Tesla coil, try making a Jacob's ladder. It gives a ton of entertainment for very little effort.