Mega Man weapon switch effect

Wave of energy washes over him to change armor color, or just over his forearm to switch between hand and buster.

Sometimes the energy wave is pixelated.

There is a method where you set up the material to be a different color when viewed through a transparent object, but is there a simpler way to do it?

Found a way. Could do with some polishing up, but it works.

Could make the set up much easier if the color ramp nodes would accept color input. Or synch different materials to use the same colors so I only have to change two.