The Final Battle (New Super Mario Bros. U)

The Final Battle, or Peach's Castle-2, is the final course of Peach's Castle and it contains the final boss of the game, Giant Bowser (with Bowser Jr. in his Koopa Clown Car). The course is unlocked via completion of Red-Hot Elevator Ride, and completing this course unlocks the portal to Superstar Road and Secret Island. This level cannot be completed with Super Guide.

Layout
The first part of the course is a short section comprised of lava and platforms similar to a Spine Coaster. Bowser Jr. will chase the player in his Koopa Clown Car, periodically attempting to drop on their head. The player can dodge the attack by moving out of the way as Bowser Jr. drops, but the young Koopa will destroy any Brick Blocks he hits on the way down. If Bowser Jr. hits the previously mentioned platforms, he will create a damaging wave that must be jumped over. The player cannot harm Bowser Jr. in this section (due to a glass dome over the cockpit of his Koopa Clown Car), so they must simply avoid his attacks as they work their way through the course.

The second part of the course begins with a checkpoint in front of an ominously large green door. After navigating a corridor filled with incoming fireballs, the player reaches the first Bowser battle, which greatly resembles the first part of New Super Mario Bros. Wii's final boss. Hitting the switch at the other side of the course causes an Axe to cut the bridge Bowser is standing on, making him crash into the pit below. After the player moves on to the final part, Bowser Jr. arrives with Kamek, who casts a spell to enlarge Bowser.

The final part of the course takes the player to a courtyard overlooked by a tower holding Princess Peach captive. Before the player can reach the princess, they must survive a boss battle with Giant Bowser. Unlike the three previous encounters, the player must directly harm Bowser by stealing Bowser Jr.'s Koopa Clown Car and crashing it down on Bowser's head. The player can also shoot a large amount of fire at bowser to defeat Bowser. While doing this, they must evade Bowser's enormous fireballs and spinning shell, as well as Bowser Jr.'s diving attacks and dropped Bob-ombs. After three strikes to the head, Bowser is defeated and the game is beaten.

Star Coins

 * Star Coin 1: In plain sight, the player must use the Wall Jump to collect it safely.
 * Star Coin 2: The player must tempt Bowser Jr. into destroying the Brick Blocks above the second Star Coin.
 * Star Coin 3: Much like the first Star Coin, the player must Wall Jump to collect the final Star Coin.

Enemies

 * Podoboos
 * Bony Beetles
 * Raining Debris (boss battle only)
 * Bob-ombs (boss battle only)
 * Bowser Jr.
 * Boss: Bowser

Trivia

 * The music which plays during the first part of the level is a slightly more evil-sounding remix of the Peach's Castle theme, which also just so happens to be the same music that plays in the world itself.
 * If completed as Nabbit in its New Super Luigi U equivalent, he'll be seen spying on Luigi and Princess Peach.