Panzer VIII Maus
Panzerkampfwagen VIII Maus ("Mouse") was a German World War II super-heavy tank completed in late 1944. It is the heaviest fully enclosed armoured fighting vehicle ever built. Five were ordered, but only two hulls and one turret were completed before the testing grounds were captured by advancing Soviet military forces.
A7V
The first tank against tank combat in history took place on 24 April 1918 when three A7Vs (including chassis number 561, known as "Nixe") taking part in an attack with infantry incidentally met three Mark IVs (two female machine gun-armed tanks and one male with two 6-pounder guns) near Villers-Bretonneux. During the battle, tanks on both sides were damaged. According to the lead tank commander, Second Lieutenant Frank Mitchell, the female Mk IVs fell back after being damaged by armour-piercing bullets. They were unable to damage the A7Vs with their own machine guns. Mitchell then attacked the lead German tank, commanded by Second Lieutenant Wilhelm Biltz, with the 6-pounders of his own tank and knocked it out. He hit it three times, and killed five of the crew when they bailed out. He then went on to rout some infantry with case shot. The two remaining A7Vs in turn withdrew. As Mitchell's tank withdrew from action, seven Whippet tanks also engaged the infantry. Four of these were knocked out in the battle, and it is unclear if any of them engaged the retreating German tanks. Mitchell's tank lost a track towards the end of the battle from a mortar shell and was abandoned. The damaged A7V limped back to the German lines, but eventually broke down.