The Pig Tank is the first midboss from Rocket Knight Adventures.
As it's name implies, this is a pig-themed tank piloted by one of the pig soldiers. The fight consists of two phases.
In the first phase you fight the Tank over a wooden bridge on a waterfall. It attacks by firing bouncing shells from the cannon on its back and by using a flamethrower on the front. Only the cockpit portion of the tank is vulnerable. A good strategy is to get behind the boss with the Rocket Burst, where it can't attack.
Once it takes enough damage, it will blow up along the bridge, with the second phase of the fight taking place as you descend the waterfall. All the boss will do is ricochet around the screen, being knocked back whenever the player hits it.