Monty Tank

Monty Tank is a Monty Mole manning a large, green tank and the boss of World 6 in New Super Mario Bros.. Monty Tank is the second Monty Mole boss in the Super Mario series, let alone the Mario franchise in general, following after Monty Mole in Super Mario Sunshine.

Monty Tank is fought at. When Mario or Luigi reaches the end of the castle, Monty Tank bumps into either of them from behind, and the boss fight begins. During the battle, Monty Tank's tank shoots out several Bullet Bills, and Mario or Luigi has to stomp the Monty Mole's head three times to defeat it. The Monty Mole's head is exposed when he comes out of the tank to throw Bob-ombs at the player, making him vulnerable to attacks. These Bob-ombs can also be thrown at the Monty Mole while his head is exposed to cause damage. Each time the tank is hit, it will spin and quickly move back and forth along the ground. While doing so, the tank makes an alarm sound go off and fires Bullet Bills from its turrets (though the amount of turrets depends on how many times Monty Tank has been damaged). Each time Monty Tank is damaged, an extra Bullet Bill shooting turret is added to the tank, making it taller and harder to hit the Monty Mole's head. After 3 hits, the tank explodes and makes the Monty Mole fall off the screen, leaving a key behind as well that allows Mario or Luigi to progress. Like the other bosses in the game, a ground pound counts as two hits; if Mario or Luigi uses a ground pound on the first hit, two turrets will be added, while ground pounding or jumping on the second hit will immediately defeat the tank. Mario and Luigi can also defeat Monty Tank by just jumping onto the tank using a Mega Mushroom. The tank is invincible when the Monty Mole's head is not exposed, though if the player stands on top of the tank, it spins back and forth to get them off it, while firing Bullet Bills and its alarm sound going off (similar to when Monty Tank is damaged).

Trivia

 * While internal data labels choropu (Monty Mole) separate from chorotank (Monty Tank), the Nintendo Player's Guide attributes the name "Monty Tank" to the Monty Mole himself.
 * Monty Tank is similar to the Monty Mole boss in Super Mario Sunshine, who similarly used a weapon, specifically a cannon, that can fire Bullet Bills from its turret, and one of its attacks also involves throwing Bob-ombs.