From the Super Mario Wiki
The Rolling Toy Block is an object found in the Game Boy Advance game Wario Land 4. The Rolling Toy Block is a mobile platform type item that Wario can ram in to move along to an area where he can stand on top of it, in a similar fashion as the Chomp Rocks from the Yoshi series, in order to reach otherwise inaccessible places to grab coins or Diamonds. The Rolling Toy Block is a circular shaped block that is red with stripes. The only stage that Rolling Toy Blocks can be found on is Toy Block Tower, in the Topaz Passage.