The Panther II is a German tank design of the Second World War based on the design of the original Panther tank. It had better armour than the Panther and adopted some standardised components from the Tiger II tank design. The Panther II did not progress beyond prototypes and did not enter production.
One prototype hull was completed and captured by US forces. It was taken to Aberdeen Proving Ground, and then later moved to the Patton museum. A Panther Ausf. G turret was placed on the Panther II hull as a placeholder. In 2010, The Panther II hull was moved to the National Armor and Cavalry Museum at Ft. Moore, GA for display.
source – wikipedia and wot youtube channel