Its not strange to see weird prototypes of tanks but this one is certainly a number one of the most mysterious and weirdest tanks of World War II. There’s only one example known to exist, which was captured by the Soviets in Manchuria, 1945 and is currently on display in the Kubinka Tank Museum, Moscow Oblast, Russia.
The tank known as “Kugelpanzer” (or “Ball Tank”) has little to none known history and no documentation exists about the tank. The Kugelpanzer was created by the Germans, most likely by Krupp, during World War II and was shipped to Japan. There’s much speculation on the tank’s purpose but most agree that it would have served as an one-man armored reconnaissance vehicle.
Its armor was only 5mm thick and the Kugelpanzer was powered by a single cyliner two-strike engine. For weaponry it would have been either equipped with a 7.92mm MG34 or MG42 German machine gun.
However the design or at least ideas for it, can be traced back to some other tanks like the German Hansa-Lloyd Bremen Treffas-Wagen (build in 1917 during World War I), the One Wheeled War Tank, the Thumbleweed Tank (design by Texas inventor A.J. Richardson) or the Russian Tsar Tank.