9. The “Kugelpanzer” was a spherical tank developed by the Nazis and believed to have been discovered by the Soviets in Manchuria
One of the more bizarre entries on this list is the spherical Kugelpanzer (“ball-tank”), a 5ft by 5.5ft cylindrical tank capable of moving at speeds of up to 8 km/h through the use of two rotating hemispheres and a stabilizing wheel attached to the rear. Lightly armored, with only 5mm of armor at its thickest point, and carrying only a single armament, likely an MG 42, the Krupp manufactured tank was not designed for an offensive purpose.
However, beyond this limited information very little is known about the Kugelpanzer due to a prescription by the Russian Federation on metallurgical analysis of the tank; in fact, almost everything else is contested by rival theories. Even the discovery location of the Kugelpanzer is not agreed, with the most common theory that it was captured in Manchuria in 1945 by the Soviet Red Army after being sent to Japan by Nazi Germany as part of a technology-sharing scheme with their wartime allies; alternatively, the Kugelpanzer might have been captured at the Kummersdorf testing grounds alongside the aforementioned Maus.
As for the intended purpose of the Kugelpanzer, in the course of World War One, the conditions of No Man’s Land significantly impeded traditional vehicle movement, prompting a slew of post-war responses involving a number of wacky and innovative designs. Among the solutions proposed were rolling tanks: first with the German prototype of the Treffas-Wagen in 1917, and later the so-called “Tumbleweed tank” in 1936 by an American inventor. Although unverifiable, it is widely suspected this was the intended purpose of the Kugelpanzer, either in a reconnaissance or infantry support capacity.