This a Bandai 1/144 kit from the Gundam universe. Its actually a fairly recent design, coming from a limited ( and largely CGI, something of a first for the show, I gather ) series that came out some 8 or nine years ago. The original kit is a kind of 'Space Pod'
adapted for combat. Given the inherent goofiness of giant robots, I decided to tweak the design a bit to give it a ground combat role...
The leg is bashed from the arms of another Gundam kit, with the big claws being fabricated from sheet. Its finished with a combination
of Alclad steel and aluminium, under two shades of Tamiya brown. a bit of wash and pastels, and here you are.
The kit itself is pretty nice, offering a number of armament and display options.
EDIT: Here's a short clip of the machine from the show:
https://www.youtube.com/watch?v=a0B5s8XRnlU