Jagdtiger Sd. Kfz. 186

This heavy self-propelled gun was constructed on the base of a Tiger II heavy tank. It appeared in 1944, and a little under 80 units were produced. 

The Jagdtiger had exceptionally strong armor: the front body was 150mm thick, 250mm on the nose, tapering along the side to 80mm. Its astounding armor drove the weight of the gun to 75 tons, making it the heaviest serially-produced fighting machine of World War II. 

The Jagdtiger design suffered from numerous problems: its suspension was unreliable, and its top speed could not be maintained, as the motor suffered from overheating. The metal required to produce one Jagdtiger could easily make four Hetzers.