Rock Block

Rock Blocks are a variety of blocks found in various games. Their physical appearance and function changes radically based on the series they appear in.

Mario & Wario
Rock Blocks are nearly identical to later appearances in Mario & Wario, being hit once to be cracked open.

Super Mario World 2: Yoshi's Island
Rock Blocks are found in many levels of Super Mario World 2: Yoshi's Island. In the Yoshi franchise, Rock Blocks are large blue blocks made of a durable type of rock, and can only be destroyed with Yoshi Eggs.

Yoshi's Island DS
The Rock Blocks from Super Mario World 2: Yoshi's Island return in Yoshi's Island DS, and only Baby Donkey Kong can destroy them with eggs or a ground pound.

Yoshi's Story
Rock Blocks appear in Yoshi's Story. They are roughly the same as in Super Mario World 2: Yoshi's Island, as they can only be destroyed by Yoshi Eggs. Golden Rock Blocks also appear in the game; they cannot be destroyed by any means.

Wario World
A different variety of Rock Blocks appeared as obstacles that Wario encountered during the events of Wario World. They can be small or very large, but each has a weak point indicated by a cracked side with a bandage on it. Wario can break these blocks by punching or Ground Pounding the weak side. The blocks can also be destroyed by using a Piledriver, Wild Swing-Ding, or Mega Toss. In some areas, Rock Blocks can move upward and slam down like a Thwomp to squash Wario.

Super Mario 3D World / Super Mario 3D World + Bowser's Fury
Rock Blocks reappear in Super Mario 3D World and Super Mario 3D World + Bowser's Fury as a gray variation of Big Blocks. They cannot be destroyed by the player on their own (except when under the effects of a Mega Mushroom), therefore, the player must make use of other means to break them, such as Bob-ombs, cannonballs, having them be hit by a Conkdor, among others.

In the Bowser's Fury campaign of Super Mario 3D World + Bowser's Fury, throwing a Green Shell at a Rock Block destroys it.

Super Mario Odyssey
Rock Blocks return in Super Mario Odyssey, retaining their appearance from Super Mario 3D World. However, they have different properties as Mario can now break them using his default abilities, such as a jump, ground pound, or Cappy toss. He can also destroy Rock Blocks whilst capturing an enemy such as an Uproot or Parabones. Rarely, Rock Blocks will contain items inside, such as coins or a Life-Up Heart.

Super Mario Maker 2
In Super Mario Maker 2, Hard Blocks take the form of Rock Blocks from Super Mario 3D World in the Super Mario 3D World level style.

Captain Toad: Treasure Tracker
Rock Blocks reappear in Captain Toad: Treasure Tracker and its Nintendo Switch and Nintendo 3DS ports, where they are identical to the Super Mario 3D World version.

Mario & Luigi: Paper Jam
Rock Blocks return in Mario & Luigi: Paper Jam, as obstacles that can be broken by the Trio Hammer move. They appear primarily in Doop Doop Dunes.