Here was a simple way to put together and make an awesome costume. It uses a terminator endoskull mask, motocross chest protector and a Andoid Morphsuit which are the basic parts of the Terminator T800 Endoskeleton costume.
With the mask, I carefully removed/trimmed the neck section to get just the skull part I wanted. With some help of the local Radio Shack store I got a couple red lights and a battery pack to give me glowing red eyes. I then installed them into a couple holes I carefully put into the mask. I also installed a couple rubber hoses onto the outer part of the mask so I had the hydraulic lines like the Terminator.
The used chest protector I got off eBay and had to repaint it silver and do some black air brushing to give it some highlights. The Android Morphsuit I had to do some alterations to the head so I could easily see through it, I basically cut out the face and resewed it so it was more like a hoodie. I bought a cheap Nerf rifle from a friend to use to help finish the costume.