From the Super Mario Wiki
Rotating Blocks, also known as Flip Blocks and Turning Blocks, are yellow, eyed blocks found in Super Mario World. When hit from below, they spin around, allowing Mario and Luigi to pass through them. Super Mario and Super Luigi can destroy them by using the Spin Jump from above. Chargin' Chuck can also destroy rotating blocks by charging into them. They seem to replace Brick Blocks from previous Super Mario games. Some blocks disguised as Rotating Blocks have items inside like ? Blocks. Also, enemies such as Koopa Troopas and Goombas may hide in Rotating Blocks, and will break out to attack Mario once he approaches him.
Rotating Blocks reappear in Super Smash Bros. Melee (as well as the remake in Super Smash Bros. Brawl), on the Yoshi's Island stage. In this game, Rotating Blocks are identical to their Super Mario World counterparts, only they are 3D (they turn 2D when rotating). They also show up in Super Princess Peach, where they look the same but had a different purpose: rather than rotating when hit, they sometimes drop an item. Also, the Boards of Super Mario RPG: Legend of the Seven Stars and Bike Pads from Mario & Luigi: Superstar Saga bear resemblance to Rotating Blocks. Aditionally, Yellow Blocks from Paper Mario resemble Rotating Blocks.