Giant Brick Block
From the Super Mario Wiki
Giant Brick Blocks, also referred to as Big Blocks, are large Brick Blocks that first appeared in Super Mario Bros. 3, where they are only found in Giant Land. In spite of their size, Super Mario and Koopa Shells can destroy these blocks.
They reappear in Super Mario Galaxy 2. However, unlike in Super Mario Bros. 3, these Giant Brick Blocks are indestructible and act as platforms rather than Brick Blocks. These are found only in the Supermassive Galaxy.
These blocks reappear in New Super Mario Bros. U. They are similar to those in Super Mario Bros. 3, as they are able to be destroyed by Super Mario or Koopa Shells. They are found only in Soda Jungle, most notably in the Jungle of the Giants level.
Giant Brick Blocks return in Super Mario 3D World, where they can be destroyed by jumping beneath them five times, ground-pounding them in Super form or better, using a Mega Mushroom, or hitting a nearby POW Block. They appear in Super Block Land. A gray variant of Giant Brick Blocks also appear, which are slightly smaller but much stronger than their regular counterparts. They can only be destroyed as Mega Mario.