Why outlets spark when unplugging - EMF & Inductors

i always though it would arc like that because of the high demand of the load being hungry for the power and the supply able to pump just a bit through the tiny air gap right as the metals lose touch (unless they get melted and explode and stuffs) and form plasma which is stretched out because of the conductivity of the plasma and grows and grows consuming more power to maintain the arc until it can no long be stable and collapses