World 7-2 (New Super Mario Bros. Wii)
From the Super Mario Wiki
World 7-2 is the second level of World 7 in New Super Mario Bros. Wii. This area features floating Water Balls that Mario needs to finish the level. It is also the only area to feature normal Chain Chomps. Bullet Bills are also present.
The level starts with Mario in front of a Chain Chomp, under a set of ? Blocks. Mario can defeat the Chain Chomp by Ground Pounding its post, releasing it and causing it to run into the wall or the edge of the screen. Next, there is a high wall that cannot be jump over; instead, the player must use a Water Ball to proceed. The next area features two Chain Chomps, followed a section with a Bill Blaster, two sets of blocks and multiple Water Balls. Another section filled with Chain Chomps is found, trapped between two walls of blocks. The player then comes to the midway point. After that, there are several more Water Balls, after which is a Warp Pipe hiding in the fog. If entered, the player must swim through more Water Balls above a pit and reach the end. The final section of the level contains Water Balls, Bill Blasters surrounding the area firing Bullet Bills onto the bubbles, and the flagpole.