Earthquake Mario is a Power-up that first appeared in Super Mario World U. It can be obtained from an Earth Rock. The Earth Rock lets you stomp on the ground to cause quakes which can make Coins fall and can make any enemy on the ground be defeated, it doesn't last long.
Super Mario World U
The Earth Rock is a new item to the Mario series. It appears Super Mario World U, when a player gets it they will turn into Earthquake form. Their coloration is brown and gray. When the player gets the Earth Rock they can stomp on the ground like Yellow Yoshi from Super Mario World. Doing this will defeat any enemies on the ground, they must be on-screen, it can also make Coins fall from the sky, even Star Coins. The effect is just like a POW Block. It only lasts for a short time. It is like the Super Star and Mega Mushroom where it lasts a short time. It first appears in World 2, it also appears in other worlds such as Giant World, Pipe Maze, Bowser's Domain and Star World.