Assist Block

Assist Blocks are golden blocks that appear in Super Mario 3D Land, New Super Mario Bros. 2, and Super Mario 3D World. There are two types of Assist Blocks: one that contains an Invincibility Leaf, and one that contains a P-Wing; these items help the player reach the end of the level, and they appear near the beginning (or midway) of the stage after losing a certain number of lives in that stage.

Super Mario 3D Land
The Invincibility Leaf Assist Block only appears after Mario loses five lives in a single level. Once Mario collects the Invincibility Leaf, he transforms into White Tanooki Mario and becomes invincible for the entire level. However, Luigi cannot obtain one unless Mario skips a normal world level (for example, by Warp Zone), as these blocks don't appear in the Special Worlds, and don't return if the level in question is beaten.

Exclusive to Super Mario 3D Land, the P-Wing Assist Block appears after Mario loses ten lives in a level. Using the P-Wing takes Mario all the way to the end of the level, in front of the Goal Pole.

If an Assist Block appears in a level, any stars on the current save file will no longer sparkle (similar to the effect of the Super Guide Block from New Super Mario Bros. Wii).

New Super Mario Bros. 2
In New Super Mario Bros. 2, only the Invincibility Leaf Assist Block returns. However, unlike in Super Mario 3D Land, the leaf inside turns Mario into White Raccoon Mario (rather than White Tanooki Mario), it will always appear if five lives are lost in a level (regardless of whether or not the level in question has been beaten), and it will disappear if any level with one is cleared without using it (restoring the sparkles on the current save file's stars as well).

Super Mario 3D World
The Invincibility Leaf Assist Block appears once more in Super Mario 3D World, working as it did in New Super Mario Bros. 2, though the White Tanooki form is retained from Super Mario 3D Land. However, the number of lost lives needed to make it appear is based on the number of players: five for one player, 12 for two, 18 for three, and 24 for four.

Super Mario 3D Land

 * Instruction manual bio: "If Mario keeps losing lives at the same point, an Assist Block will appear. Hit it to receive a special item."

New Super Mario Bros. 2

 * Instruction manual bio: "If Mario loses five lives in the same course, an Assist Block will appear. Hit it to release an Invincibility Leaf and transform into White Raccoon Mario."