Soda Jungle

Soda Jungle is the fifth world of New Super Mario Bros. U. It is the largest world in the game, both physically and in terms of courses. 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 4 from New Super Mario Bros. in terms of appearance, layout and theme as the jungle is giant-themed within both the world map and the normal levels, as well as big enemies or big variations of small enemies, like Grand Goombas and Gargantua Koopa Troopas. The dead trees in the center of the jungle leads to a haunted area, containing a few extra courses, including Boo enemy courses. When the player enters the area, the area pixelates before loading again. The name is derived from soda as a reference to the acid water in the world. There are twelve levels in this world, with the first Airship level appearing before entering the section, five normal levels in the outer areas, two that are in the haunted area along with the second Ghost House and the Boo Enemy Courses, a secret level, the Tower level and Castle level. A green Toad House and two red can be found here as well. The boss of this world is Iggy Koopa.

There are several ways to enter this world. Completing Wendy's Shifting Castle or Larry's Torpedo Castle will bring Mario to The Mighty Cannonship, the first airship in the game. However, completing Blooper's Secret Lair or Piranha Plants on Ice, Acorn Plains and Layer-Cake Desert's secret levels respectively, will immediately take Mario to Jungle of the Giants.

In the haunted area in Soda Jungle, Mario must take an alternate exit in either Painted Swampland or Deepsea Ruins in order to create a pathway that will allow him to leave the haunted area and proceed through the world, in a manner similar to the Forest of Illusion in Super Mario World; taking the normal paths otherwise in either stage will bring him back to the pathway in front of Which-Way Labyrinth.

Challenge Mode original courses

 * Airship 1-Up Rally - 1-Up Rally
 * Be Gentle to Giants - Special
 * Big Goomba Bounce Bash - 1-Up Rally
 * Bowser's Airship Sneak - Special
 * Marathon Glide - Special
 * Poison-Swamp Scramble - Time Attack
 * The Boo Ballet - Time Attack (Original Course)
 * The Boo-Ballet Encore - Time Attack (Original Course)

Boost Rush Courses

 * Painted Swampland – Expert Pack
 * Iggy's Volcanic Castle – Expert Pack

New Enemies

 * Cannons
 * Cannonballs
 * Giant Cannonballs
 * Mecha-Koopas
 * Red Skull Boxes
 * Targeting Teds
 * Mecha Cheeps
 * Bowser's Claw (cameo)
 * Grand Goombas
 * Mega Goombas
 * Gargantua Koopa Troopas
 * Piranhacus Gigantici
 * Bramballs
 * Stalking Piranha Plants
 * Amps
 * Big Amps
 * Ball 'n' Chains
 * Broozers
 * Scaredy Rats
 * Bulbers
 * Jellybeams
 * Wigglers
 * Mega Wigglers
 * Para-Beetles
 * Heavy Para-Beetles
 * King Bills
 * Magmaarghs
 * Boss: Bowser Jr.
 * Boss: Iggy Koopa

Trivia

 * This is the only world in the game with more than one section: The haunted forest sub-area, the outside and the inside. This is similar to World 3 of New Super Mario Bros. Wii, which also had multiple sections.
 * Every world before Soda Jungle leads to the latter, either by a world-skipping shortcut or completing the previous world's castle, and, Soda Jungle leads to every world afterward, besides Peach's Castle.
 * Soda Jungle, Meringue Clouds, and Layer-Cake Desert are the only three worlds to have three Toad Houses, two red and one green.