Man the p1000 Landkreuzer ( Ratte ) would have been a sight to see, 1000 tons of megalomaniacal German engineering.
Guns from a battleship, submarine engines & almost impervious armour.
Unfortunately it would have only capable of moving in flat(ish) open country ( Russian steppe, deserts, etc )
.. but I still love the out of the box Lunacy that got this to the blueprints stage.
Peace bro 😉