Earthbending-powered tank

Earth Kingdom Tanks, also nicknamed by some as Slinky Tanks, are vehicles owned and operated by the Earth Kingdom Military. They first premiered in The Day of Black Sun, Part 1: The Invasion.

Overview
The Earth Kingdom Tanks were first proposed shortly after the fall of Ba Sing Se. Sokka of the Southern Water Tribe decided that if the Earth Kingdom and Water Tribes were going to invade the Fire Nation on the Day of Black Sun, they were going to need vehicles to mow down the defenses. Sokka designed the tanks himself and introduced his plans to the Mechanist, a expert inventor and ally of the Avatar's gang. The Mechanist immediately set forth to start building these vehicles.

Design
The Earth Kingdom Tanks are multi-segmented tracked vehicles powered by four Earthbenderss. They can carry many troops and can cross over almost any terrain. Their armor is invulnerable to fire, making them ideal for assaults on enemy positions. Powered by Earthbending, these tanks can be manipulated to crush enemy targets, including tanks and even small bunkers. They can swerve around enemy forces easily and make good shields for ground troops. They even sport side hatches that open up so that Earthbenders can launch projectiles like rocks and boulders at enemy troops.

Weaknesses
If Earth Kingdom Tanks are knocked on their sides, they are helpless on the battlefield until they are set up straight again.

History
During the invasion of the Fire Nation on the Day of Black Sun, at least five Earth Kingdom Tanks were deployed on to the shores of the Fire Nation Capital from the Water Tribe Submarines. These Tanks proved amazingly durable and were able to withstand repeated attacks by Fire Nation Tanks. They crushed many of these tanks and entire bunkers, as there were dozens of these small structures lining the Capital grounds. The Tanks got the invaders to the Royal Plaza and then proceeded up to the Royal Palace.

During The Day of Black Sun, Part 2: The Eclipse, these Tanks once again overwhelmed enemy troops and eventually captured the Palace. Unfortunately, the Fire Nation was ready for this and once the solar eclipse ended, the Fire Nation launched their airships to drive out the invaders. The invaders tried to escape the Capital in their Tanks, but it was way too late to reach the submarines, as the airships destroyed these craft with their bombs. After the invasion failed and the Avatar's group escaped, the invasion force was left behind to surrender to the enemy.

The Tanks all survived the battle, but it is unknown what the Fire Nation has done with these vehicles.