After seeing the Electric chair illusion costume on this site (made by John), I also wanted to do one. Mine is slightly different but is also just as awesome!
I had to carefully measure the height of the seated area when I was standing so it didn’t look elevated but also had to match the height of my hips. Since everyone has a different height, and length of legs, you will need to customize it to fit YOU. I’m 6′ tall in my case.
I first went and obtained some new cardboard boxes and started taping the pieces together followed by notching out the parts to fit together. I would later wrap it all in silver duct tape. I also bought a metal mixing bowl since it was reflective and glued some flickering tea lights inside to mimic being fried. This is held onto my head with a leather strap that was bolted to the bowl. I attached that to some conduit from Home Depot down to a plate attached to the backside to appear realistic, like a receptacle.
I used some adjustable dryer hose clamps as wrist restraints which doubled as handles when I was walking around. A PVC frame was added to the inside of the cardboard so I could attach some straps so that my shoulders could carry it. It was very light so I could walk all night. In addition to using panty hose filled with polyfill for the legs inside the jumpsuit, I added an iPod nano and bullet speaker inside looping electric sounds aimed forward.
I have to say, with my Electric Chair illusion costume I was the most popular guy in downtown Savannah last year!