World 3-1 (New Super Mario Bros. Wii)
From the Super Mario Wiki
World 3-1 is the first level of World 3 in New Super Mario Bros. Wii. It is a snowy level which introduces a new penguin-like enemy, the Cooligan. It also introduces a new power-up, the Penguin Suit, which allows players to shoot ice balls, move more easily on icy surfaces, and swim more easily. Completing this course unlocks World 3-2.
The level starts with ? Blocks and Cooligans coming towards the players from the right. Past the Cooligans are bumpy ice platforms along with two Piranha Plants and a ? Block containing a Penguin Suit. Past this area are Koopa Troopas and more Cooligans, along with the midway point and a Warp Pipe. The Warp Pipe leads to a new area with a Red Ring and another ? Block containing a Penguin Suit. The players can slide along an icy roller coaster-like track using the Penguin Suit to collect the Red Coins and reach the flagpole while jumping to avoid more Cooligans and Koopa Troopas.
The Penguin Suit is required for all three Star Coins.