Wobble Rock

Wobble Rocks are a type of rock platform originating from Super Mario World 2: Yoshi's Island. They wobble from left to right when the player stands towards one of its edges.

Super Mario World 2: Yoshi's Island
Rolling rocks, also referred to as crumbling ledges, first appear in Super Mario World 2: Yoshi's Island. They are rock platforms balancing on the tip of a pillar, and when one is landed on, it begins weighing over to the side it was landed on, eventually falling over. Only one appears each at the start of Raphael The Raven's Castle and Kamek's Revenge, after a sequence of similar-looking pillars outside.

Yoshi's New Island
A few Wobble Rocks appear in Yoshi's New Island, specifically in certain areas in the level Cruise the Clouds. They behave the same as in Super Mario World 2: Yoshi's Island and the New Super Mario Bros. sub-series, but come in two sizes.

New Super Mario Bros.
Rolling rocks return in New Super Mario Bros., behaving the same as in Super Mario World 2: Yoshi's Island. They only appear in World 8-5.

New Super Mario Bros. Wii
Half-circle rocks reappear in New Super Mario Bros. Wii, behaving the same as in New Super Mario Bros., though they can now be re-balanced by standing on the side opposite where they were weighted down. They only appear in World 8-1.

New Super Mario Bros. U / New Super Mario Bros. U Deluxe
Wobble Rocks appear yet again in New Super Mario Bros. U and New Super Mario Bros. U Deluxe. Their behavior is largely unchanged from its past appearances. They appear only in the level Walking Piranha Plants!, though they also play major roles in the challenges Balancing Act and Wobble and Rock. Wobble Rocks are among the few objects that do not return in New Super Luigi U.

Donkey Kong Country: Tropical Freeze
Teetering platforms similar to Wobble Rocks appear in Donkey Kong Country: Tropical Freeze in Crumble Cavern, where they are constantly pushed from left to right by periodically overfalling streams of water.

Super Smash Bros. series
In Super Smash Bros. for Wii U and Super Smash Bros. Ultimate, a giant Wobble Rock comprises the Rock-Candy Mines portion of the Mushroom Kingdom U stage.