World 4-3 (New Super Mario Bros. 2)
From the Super Mario Wiki
World 4-3 is the third standard level of World 4 in New Super Mario Bros. 2. The level contains many Piranha Plants and has a background that is very reminiscent of Donut Plains from Super Mario World. The player can manipulate the slopes to Slope Slide and gain great speed.
The level begins with Mario on icy floor in front of a gap with a Piranha Plant. There is a Koopa Troopa above a set of blocks, with the ? Block containing a Fire Flower. Right after is a Gold Ring. Following that is an icy slope with many Goombas and Piranha Plants. After the slope there is a Red Ring, which causes Red Coins to parachute down. There are also several gaps on the ground which are full of Piranha Plants. The Checkpoint Flag can then be found. Another Fire Flower can then be found in a ? Block. More Piranha Plants can be found. Mario then has to climb up several icy platforms in the air to a high ice cliff. A P Switch can be found here, where Mario can collect blue coins by sliding down another slope, avoiding Piranha Plants and a Big Piranha Plant. Then, a ice staircase can be found, followed by the Goal Pole.