Canned Nazis, bouncing over the hills
Not much is known about this WWII "spherical droid" - captured on the Eastern Front (in Manchuria) in 1945 and currently on display in Military Museum in Kubinka, Russia. This "brainchild" of German military thought had 5mm armor, driver's cab inside and two-stroke one-cylinder engine. By all appearances this machine was used as a reconnaissance vehicle.
Multiple inquiries about the origins of this machine, made to German historians and tank specialists, so far draw a blank. It is speculated that Krupp could have built this as Reconnaissance Rollzeug (Rolling Vehicle). Thus it's often referred to as "Krupp Kugelpanzer", or "Ball Tank". Note the narrow-slitted visor at the front, and imagine a poor soul canned in such a fashion and sent bouncing down the hill...
Similar "Ball Tank" concept from an engineer in Texas:
Popular Science, July 1936 described it as "a giant ball, a high-speed "tumbleweed tank" with a spherical hollow steel driving cab, enclosed by a rotating outer shell... The inventor states that the tank’s spherical shape presents the smallest possible target for enemy bombs or shells, and all but direct hits would glance off its curved sides." Not so impractical, after all, regardless of how crazy it looks.
ven earlier, there was a wilder concept:
War Tank on One Wheel
Popular Science, November 1933 - "Housed inside the armored body, the operator will steer the single main wheel by means of two small auxiliary wheels at the rear... by attaching propelling fins to the main wheel, the tank can be turned into an amphibian capable of plunging into a stream... As the tank rushes upon a trench or obstruction, the operator will drop the tubes so they dig into the earth and the whole machine will vault through the air to the other side! Without the armored body or the crutches, it is designed for highway use.
One-wheeled tanks were imagined before first World War in a quite spectacular way - the ultimate rolling destruction machine: