Somehow a human is hiding inside of this Metal Gear REX costume. The creation requires two additional people for assembly purposes, as shown in the video below. According to Pro Voltage Cosplay, the costume is by Ruby Taki and took seven months to create. Tiger Shot Productions captured the striking image above.
In the Metal Gear mythos, REX is a mech with the ability to launch an undetectable nuclear device with a rail gun. It is a big, scary machine that appears in some capacity in many Metal Gear games and even Super Smash Bros. Brawl. The machine is operated from within by a pilot, so sure, in some silly fictional accuracy to a human hunkered inside of the outfit.