The German giant mortar Mörser Karl Gerät Nr. III to Odin, used against the Soviet fortress of Brest, in the early stages of Operation Barbarossa in June 1941. Beside's the Munitionsschlepper (ammunition loader), PzKpfw IV converted.
Panzer VIII Maus was a super-heavy tank that remains the largest fully enclosed armored fighting vehicle ever built. Designed by Dr. Ferdinand Porsche, the Panzer VIII was 50 percent longer than the next largest German tank and was over three times as heavy.