Penguin Suit

The Penguin Suit is an item in the game, New Super Mario Bros. Wii; as its name suggests, it is a suit that resembles a penguin. This item first appears in World 3, and from then on it is found in Toad houses as well. It allows players to turn into their Penguin form, that has a blue or black body with short, colored trousers. The suit lets the player throw ice-like snowballs at enemies, freezing them (just like the Ice Flower); this not only prevents them from hurting the player, but the frozen enemies can also be used as platforms. It also improves traction, making players not slip while on ice. In addition, the Penguin Suit lets the player swim more efficiently underwater, and even slide on ice and water without sinking, breaking any blocks they collide with. It is even able to defeat enemies, but will bounce off a sliding Cooligan unhurt. It is introduced along with the Propeller Mushroom as the newest power-ups in the game.

penguin suit reappears in New Super Mario Bros. U being used for the same purpose, but the purpose can only be found in a Toad House from Superstar Road

Trivia

 * The Penguin Suit seems to mimic the shell dash function of the Blue Shell from New Super Mario Bros. as both items allow the wearer to slide along surfaces at faster speeds than running.
 * The Penguin Suit is also similar to the Frog Suit of Super Mario Bros. 3, allowing the player more control in the water.
 * The Penguin Suit is rather similar to the penguin suit in the Wii Fit game "Penguin Slide".
 * When a character obtains a Penguin Suit, the sound effect is slightly different from other power-ups. A sound similar to a duck quacking is played along with the normal power-up sound.