From the Super Mario Wiki
Donut Lifts (also known as Donut Blocks, Falling Blocks or donut platforms) are a kind of platform first appearing in Super Mario Bros. 3. They get their name from the fact that they are round (except for the top) with a hole in the middle. If the player stands on one for more than a second, it drops below. For this reason, Mario and Luigi should avoid touching the ground by jumping as much as possible when crossing Donut Lifts. In Super Mario Advance 4: Super Mario Bros. 3 there are spiky variants only available on the e-Reader levels.
Super Mario World 2: Yoshi's Island and its remake Yoshi's Island: Super Mario Advance 3, as well as the sequels Yoshi's Island DS and Yoshi's New Island, also contained Donut Lifts. In Yoshi's New Island, a variation that is four times the normal size appears. Super Mario RPG: Legend of the Seven Stars additionally featured them, accurately adapting their platforming concept into its isometric field gameplay. They also appear in Super Princess Peach, New Super Mario Bros., Mario vs. Donkey Kong 2: March of the Minis, and New Super Mario Bros. Wii where they do the same thing. Super Princess Peach in particular also had blue versions, that, if stood on, drop almost immediately, so fast that Peach needed to use Gloom to make it over.
Donut Lift-like platforms appear in Super Mario 64 and its remake, Super Mario 64 DS; these possible Donut Lifts resemble their two-dimensional counterparts, but are shown to be rather long (whereas Super Mario RPG previously showed confirmed "three-dimensional" Donut Lifts to more square-shaped than rectangular). In Hazy Maze Cave there are lifts to help the player get Elevate for 8 Red Coins (choose the direction) and Underground Switch Star (In Underground Switch Star, the Donut Lifts are not required). In Lethal Lava Land's volcano, they appear near the top, along with the moving platforms. In Rainbow Ride, most had to be jumped over during the magic carpet ride and some served as bridges to other parts of the level. Long Donut Lifts of this style are also seen in Mario & Luigi: Superstar Saga, but only in Guffawha Ruins. In Mario & Luigi: Bowser's Inside Story they appeared once when Luigi accidentally steps on one in the Flab Zone, making him fall into a mucus pit and summoning Princess Lipid.
There are also a yellow bars with grooves on their ends. When Mario walks over or hangs on them, they will behave similarly to Donut Lifts, turning red for a second before falling down. This variety appears only in World 4-2 of New Super Mario Bros. Wii.
Donut Lifts reappear Super Mario 3D Land. However, in this game, when being stomped on, they immediately fall down slowly and disappear below the stage. A rock variation exists, and it has the same effect.
The Donut Blocks make an appearance in New Super Mario Bros. 2. Glacial versions of the Donut Lifts also appear in the snow world (World 4). These Donut Lifts are slippery and can be differentiated from the ordinary Donut Lifts by it's light blue colour. Other than being light blue and slippery, they share every characteristic of the normal Donut Lifts.
Donut Lifts also appear in New Super Mario Bros. U with the same functions as in the other games.
In Mario & Luigi: Dream Team, Donut Lifts appear in area B of Dreamy Neo Bowser Castle. They retair their colors from the New Super Mario Bros. games, but are much thinner, stretched and rounder this time around. They function similarly to Super Mario 3D Land, where, once they are stepped on, they turn red and fall after a short time.
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