you need to take a trip to a hardware, home improvement store. Get a role of bubble rap insulation normally used for rapping duct work. It is in a cylinder shape already. Cut out openings for face and arms. I left a way to get into it through the back using Velcro strips. Cut out a circle for the top. I used black duct tape to attach it. Use a spray paint cap for the top of the battery. Decorate with permanent markers.
My son was an energizer because he keeps going and going.
Thanks BugsMom1 for this different idea.