Snake Block

Snake Blocks, also known as Caterpillar Blocks, are blocks usually found in castle-type levels. They first appeared in Super Mario World, and re-appear in Super Mario Advance 4: Super Mario Bros. 3, the New Super Mario Bros. games, and Super Mario Galaxy 2. In all games, they are a set of blocks resembling the Empty Blocks from Super Mario World that start out as a normal platform and begin to move like a snake when stepped on by Mario or Luigi. Snake Blocks can turn left, right, up, or down as they follow a predetermined course over obstacles such as a wide pool of lava, a bed of spikes, or a bottomless pit. Mario must continue to move and follow it when on these blocks, otherwise they keep moving under Mario's feet, and he may possibly fall off.

Snake Blocks get their name from the classic arcade game , in which the player controls a sequence dots that resemble the snake animal.

Super Mario World
In Super Mario World and Super Mario World: Super Mario Advance 2, Snake Blocks consist of normal Empty Blocks, and are found in #5 Roy's Castle and #7 Larry's Castle.

Super Mario Advance 4: Super Mario Bros. 3
Snake Blocks return in Super Mario Advance 4: Super Mario Bros. 3, in which they only appear in the World-e levels A Towering Tour and Vexing Doors, and they now consist of Rotating Blocks from Super Mario World rather than Empty Blocks.

New Super Mario Bros.
In New Super Mario Bros., Snake Blocks are bright green rather than brown, and only appear in World 7-Castle and World 8-Tower 2.

New Super Mario Bros. Wii
A similar Snake Block called the Ice Snake Block appears in New Super Mario Bros. Wii. It is found in World 3's Castle, but unlike regular Snake Blocks, its icy surface is slippery, though the Penguin Suit can remedy this fact. Normal Snake Blocks are unused in New Super Mario Bros. Wii.

Super Mario Galaxy 2
The Snake Blocks in Super Mario Galaxy 2 appear in the Boo Moon Galaxy, Bowser's Lava Lair, and Bowser's Galaxy Generator. In this game, they make their only 3D appearance, though they are used in the same way, and are colored pink. It is first shown here that they can be of varying widths, instead of only one block wide, as in its previous 2D side-scrolling appearances.

New Super Mario Bros. 2
Snake Blocks reappear in various levels in New Super Mario Bros. 2, where they have the same appearance they have in New Super Mario Bros. This is the first time they are seen moving on their own. Also, this is the first time that they are not only used as platforms to cross gaps, but also as obstacles, especially in World 1-Tower. They are much more common in this game compared to the previous New Super Mario Bros. games.

New Super Mario Bros. U / New Super Luigi U
Green-colored Snake Blocks reappear in New Super Mario Bros. U and New Super Mario Bros. U Deluxe, but are now less commonly used than in previous games. Giant Snake Blocks also appear, being found only in Snake Block Tower. In New Super Luigi U, they appear in Stone-Snake Tower.

Super Mario Maker / Super Mario Maker for Nintendo 3DS
In Super Mario Maker and Super Mario Maker for Nintendo 3DS, Snake Blocks can be reproduced by placing a long row of blocks onto a track. They also make an appearance in World 15-4 of the Super Mario Challenge of the latter version.

Super Mario Maker 2
In Super Mario Maker 2, Snake Blocks make an appearance as a full course element. The path that the Snake Block follows is set by the player. In the Super Mario World style, Snake Blocks are green, rather than made of regular Empty Blocks as they are in the original game. There is also a blue variety known as Fast Snake Block which, as the name suggests, is faster than the green one.

Mario Party 10
Snake Blocks reappear in Mario Party 10 in the minigame Snake Block Party.

Super Mario Maker 2

 * North American website bio: "Draw a path and the Snake Block will follow!"