Also known as: カッパガンダム
Kappa Gundam is a Mobile Fighter for Neo Japan featured in Newtype Magazine, and briefly in Mobile Fighter G Gundam.
It's designed for aquatic combat and does poorly on land. The turtle shell is actually a specially-made core lander. It's armed with cucumber-shape beam saber.
According to the "Only! My Gundam" description, it was representative of Neo Japan during the 11th Gundam Fight, but later ends up in the hands of Neo Denmark some time before the 13th Gundam Fight.