Plasma, like solid liquid and gas is considered a state of matter. Plasma is ionized gas, and can be created by applying energy to a gas, like electromagnetic or electrical energy like this transformer. As you can see it puts out an extremely powerful arc of electricity, But its hiding a cool secret we cant see with our own eyes. At 10x slow motion we begin to see a flickering light, this is caused by the AC or alternating current that comes out electrical outlets. the alternating current reverses direction 60 times per second, which causes the flicker. The blue light in the center is the electrical arc, its so hot its turning the surrounding air into plasma.