first Prototype was to be ready before spring of 1943 . Krupp was in charge of producing the Hulls and Turret which were to be assembled by Alkett. Because of repeated changes in the armament the production of the prototype was delayed until summer 1943 ( which again was delayed until December 1943). The unit was to be armed with 128 mm gun and it was planned to produce 5 units per month if the project was succesful. A wooden mock up was shown to Hitler in the summer. Hitler ordered a Series of 150 to be produced as soon as possible ( the order was cancelled on November 1943)
The final unit witouth turret was produced in December of 1943.Though it was planned for the vehicle to have the maximum speed of 20km/h the unit couldn't go faster than 13km/h even in ideal conditions. the other serious problem caused by its heavy weight was that there was not a single bridge that could take its weight. This problem was solved by installing Snarkel which allowed Maus to go under water.
On March of 1944 , second prototype was perpared ( Maus II) . Maus II lacked power plant which was installed in Mid 1944. In April Krupp produced the turret . Finally Maus was armed with 128mm KwK 44 L/55gun. the gun could penetrate the frontal armor of any tank at range of 3500m.
to transport Maus an special railroad transport was produced . Maus was trasported to Kummersdorf testing grouds near Berlin. Test were long and delayed by several engine failures and production delayes caused by allied bombings on German Cities anf factories. During the tests it was determind that in case of any failure a single Maus had to be towed by two other Maus units.
After the tests Hitler canceled any firther developments on Maus and the 2 other hulls in krupp facility to be scrapped. the only unit built saw action during the defence of the facility at Kummersdorf.
Maus was designed to be invinsible and it was truely an intresting design but because of its limited combat value caused by its low speed it was more of a mobile fortification than a super heavy tank. some sources say that Hitler wanted to use Maus as Mobile coastal batteries in his Atlantic wall.