This custom was produced by UK artist, Cris Rose and is a custom built Koibito figure, originally designed by Yoskay Yamamoto. It's called 'Project K' and has quite a detailed backstory to it!
Project K is a machine created to combat the evil Japanese whalers of the distant future (2118, to be precise). Project K is a deadly amphibious robot, capable of destruction on both land and sea, and the scourge of all whalers off the coast of Japan.
According to Tomopop, the custom is built from acrylics, resin, metal, and an assortment of found objects.
The original Koibito colorway versions by Yamamoto[VIA]