Halloween costume

 My son wanted to be Iron Spider for Halloween this year. 

(The photo is from our trunk or treat this year. I literally googled "spiderman trunk or treat" found an idea, and just copied it cutting out pieces from colored plastic table clothes)

Here is what iron spider looks like for reference.

We got an Iron Spider costume, but it obviously didn't come with the arms... So I started thinking how I could make the arms without also having him maim other kids walking down the street.

Then I remembered a last minute Halloween costume by Adam Savage from the Mythbusters,

So I got some 1/4" aluminum armature wire, and the insulation with adhesive on one side you use to insulate door jams. I stuck the insulation to itself on either side of the wire, then shaped it with some scissors, and spray painted it gold.

My wife then got an old backpack from a friend, cut everything off but the back pad, and the straps. She the cut a piece of wood to size, and drilled some holes with a jig to hold the arms in place. We fit the wood to the backpack with some screws (flat on the side that would be touching his back) then used colored duct tape to cover everything and fit with his costume.

He was pretty happy with how it turned out.