Frosted Glacier

Frosted Glacier is the snowy fourth world of both New Super Mario Bros. U and New Super Luigi U, lying northeast of Layer Cake Desert, Sparkling Waters, and Acorn Plains, north of Soda Jungle, northwest of Rock-Candy Mines and Meringue Clouds, and west of Peach's Castle. Frosted Glacier is a cold and snowy world with pine trees and indigo mountains similar to World 5 from New Super Mario Bros., only to take place during a constellation-filled night. It's one of two of the worlds that the player can choose from after beating Morton in Morton's Compactor Castle (Morton's Lava-Block Castle in New Super Luigi U), the other being Sparkling Waters. Because of this, it is quite possible to play through the game without ever reaching Frosted Glacier. There are 9 levels in this world, five of them are the regular levels, two are the Tower and Castle levels, one Ghost House, and one secret level. The name is derived from frosting, or a reference to the original meaning, which is to be covered and coated in frost. The boss of this world is Wendy O. Koopa. The Bubble Baby Yoshi makes their appearance on the map. There are Cooligan Enemy Courses.

Challenge Mode Original Courses

 * Bullet Bill 1-Up Bounce - 1-Up Rally
 * Fliprus Crossing - Time Attack
 * Ghost House Coin Curse - Coin Collection
 * Icicle Skating - Time Attack
 * Penguin Bowling - 1-Up Rally (Original Course)
 * Prickly Goomba's Coinless Run - Coin Collection
 * Slick Slopes and Bullet Bills - Time Attack

Boost Rush Courses

 * Spinning Star Sky – Flying Squirrel Pack
 * Wendy's Shifting Castle – Acrobat Pack
 * Fliprus Lake – Penguin Pack
 * Cooligan Fields – Penguin Pack

New Super Mario Bros. U

 * Munchers
 * Cooligans
 * Prickly Goombas
 * Bullet Bills
 * Bill Blasters
 * Banzai Bills
 * Banzai Bill Cannons
 * Ice Bros.
 * Big Boos
 * Flipruses
 * River Piranha Plants
 * Thwomps
 * Big Thwomps
 * Thwimps
 * Boss: Wendy O. Koopa

New Super Luigi U

 * Broozers
 * Ice Piranha Plants
 * Cooligans
 * Bony Beetles
 * Prickly Goombas
 * Banzai Bill Cannons
 * Buzzy Beetles
 * Boos
 * Big Boos
 * Flipruses
 * Thwomps
 * Big Thwomps
 * Boss: Wendy O. Koopa

Trivia

 * Like in New Super Mario Bros. Wii, the music for the snow overworld levels is a winter-themed arrangement of the regular overworld theme in the game.