Soda Jungle

Soda Jungle is the forest world in New Super Mario Bros. U and can be the fifth area in the game if the player chooses the other way. It can be reached by completing Wendy’s Shifting Castle and going south, or by completing Larry's Luminant Castle and going north. This world, as the name implies, takes place in a jungle that's inspired by Big Island from Super Mario Bros. 3, Forest of Illusion from Super Mario World and World 5 from New Super Mario Bros. Wii in terms of appearance, layout and theme as the jungle is giant-themed within both the world map and the normal levels, which there are 5 of in this world, as well as giant versions of enemies, like Grand Goombas and Gargantua Koopa Troopas. The name is derived and is a reference to Soda Lake. There are seven levels in this world, with five normal levels, the Fortress level and Castle level.

The boss of this world is Iggy Koopa, who is the boss of both the fifth world in the game (like he was the boss of World 5 in the Wii predecessor) and the boss of a big-themed world (much like how he was the boss of Big Island).

Levels

 * Soda Jungle-1: Jungle of the Giants: The first level of Soda Jungle. It introduces Mega Goombas and Gargantua Koopa Troopas and includes giant Brick Blocks.
 * Soda Jungle-2: Bridge Over Poisoned Water: The second level of Soda Jungle.
 * Soda Jungle-Tower: Snake Block Tower: The Tower level of Soda Jungle.
 * Soda Jungle-3: Bramble Jungle: The third level of Soda Jungle.
 * Soda Jungle-4: Painted Swamp Land: The fourth level of Soda Jungle. A haunted level with Poisonous Water, slanted Warp Pipes, Boos and Circling Boo Buddies. Its background resembles Vincent van Gogh's painting style (most especially "The Starry Night"), and a picture of Bowser in this art style can be seen in the background.
 * Soda Jungle-5: Deepsea Ruins: The fifth level of Soda Jungle.
 * Soda Jungle-Castle: Iggy’s Volcanic Castle: The Castle level of Soda Jungle.

Challenge Mode original courses

 * Mole to Goal
 * A challenge where Mario has to avoid groups of Circling Boo Buddies and get to the goal for a certain amount of time.