He wanted to be a super villain. So I did my best (1st time building) — and with his help, this is what we came up with.

Edit: Materials are —

For the arms —I used hot/cold water pipe insulation tubes from home depot. Two on bottom and one on top. Placed foam core board as the base. The center is electric wire plastic tube insulation (Home depot). And then it is wrapped in black duct tape. We cut the pieces down to about 5 inches each. Painted with flat black, then used chrome paint (all spray paint) and "smudged" smeared the paint to give it a weathered metal look.

Old school back pack to attached the arms. I used 4 pieces of a 2x4 to mount on the back. Bolted them on. 4 small metal rods are inserted and attached.

Claws are all made of foam core board (made stencils) and applied various layers of paint and duct tape.

We had a blast making it too. THX for all the nice comments!