Wierd costumes are a bit of a thing for our family. So when my son requested to be an eyeball for Halloween, I didn't bat an eye. Having made a few pinatas in my time, I decided to take the paper mache and balloon approach and just make it bigger.
A trip to a local party supply wholesale warehouse turned up the biggest balloon we could find. Although the package claimed it could be inflated to a three foot diameter, I wasn't feeling terribly brave so we went a little smaller than that.
Covering the balloon with paper mache took about a week, letting it dry completely between each layer. We used a combination of water, flour and craft glue for the paste, just mixed until it was fairly liquid and smooth because we wanted a smooth outer layer. When covering the balloon, I made sure to alternate between laying the newspaper strips horizontally and vertically to make it stronger. I popped the balloon when it had hardened to the point where we could knock on it and is sounded pretty solid. There were a couple of spots that felt a little weak after the balloon was gone, so we reinforced with a bit of duct tape.
I cut the bottom, top and arm wholes with a box cutter, finishing the rough edges by folding duct tape over them. We used printed newspaper, so it took several layers of white spray paint to cover the print. The iris, veins and pupil are painted on in acrylic paint and then we topped the whole thing off with a payer of clear spray paint.