Boost Block

A Boost Block is a special block that is found in New Super Mario Bros. U and New Super Luigi U. Boost Blocks can be used only in multiplayer mode, and to use one, a player must tap the Wii U GamePad screen. Boost Blocks are intended to serve as platforms to help Mario and company progress in a level. There are other uses for Boost Blocks, such as placing them above characters' heads to prevent falling objects such as Thwomps from harming them and stopping enemies from exiting a pipe. A Boost Block can even block the Mecha Hand in Boarding the Airship (Bowser Jr. Showdown in New Super Luigi U). If a player steps on a Boost Block while a symbol is shown, the block releases three coins while filling the Boost Star meter, though if a player steps on a block without a symbol on it, the Boost Star meter disappears, no matter how full the meter was before disappearing. If a player steps on 10 Boost Blocks with a symbol shown in a row, a Boost Star appears, and the player using the GamePad can tap it to gain Boost Star power. Boost Blocks cannot be used in New Super Mario Bros. U Deluxe.

Boost Blocks also appear in the mode Coin Battle, where they are used as platforms for the winning players in a cutscene. This variant features a star icon, and the color is determined by the playable character's color.

If a player gets 99 lives, the Boost Blocks are shrunk into small square Mini-Boost Blocks, making them more difficult to land on. However, the Boost Star meter becomes easier to fill because the playing-card symbols do not disappear while Mini-Boost Blocks are onscreen.

Mini-Boost Block
Blocco Assistente Boost-Block