Level B-23 is the seventh course in the Bonus 3 set and the twenty-third Bonus Level overall in Mario vs. Donkey Kong: Tipping Stars. It is set in Clattering Cabin and is unlocked by earning 86 trophies.
The course is an expansive arrangement of halls, floors and other platforms, interconnected by Split Pipes and Movable Pipe outlines. Rivets for Red Girders and Blue Lifts are scattered throughout the stage as well, but the player is not initially provided with such materials to use. Instead, the Minis must be lured into various Pickups to add pieces to the player's resource stash, giving them the possibility to connect rivets. In addition, Long Spring slots are mostly found in the right portion of the level where they can be turned functional to bounce the toys to higher areas.
The Cursed Mini Mario starts on a platform in the center of the stage and soon falls onto a floor of spikes at the bottom. Marching onward, it bounces off a Long Spring to a platform above, but soon falls back to the bottom through a gap and enters a magenta Split Pipe in the floor. The pipe warps it higher up in an area with Long Springs, where it will use two functional ones to reach a yellow Split Pipe further to the left. Navigating some other Split Pipes, the toy ends up near its starting point from where it will proceed the same march around the level if undiverted.
Most Minis are initially involved in precarious situations, such as the Mini Mario and the Mini Luigi starting in a room on the left where they cannot escape without Blue Lifts, and the Mini Pauline, the Mini DK and the Mini Toad facing a gap with spikes at the bottom, which they cannot cross without Red Girders. Only the Mini Peach and the Gold Mini Mario have proper paths to follow and must collect Pickups on the way to help the other toys and recruit them. Eventually, the Cursed Mini Mario also has to be recruited as a normal Mini Mario by attacking it a pair of Hammers found at the mouth of a gray Split Pipe in the middle.
When all Minis are in tow, they should be escorted to the Goal Door on the bottom floor by stretching a long Red Girder over the pit of spikes towards the door.
The M Coin is located in the bottom left under Mini Mario's and Mini Luigi's starting positions, between two pairs of Blue Lift Rivets. Either the two Minis can descend there with Blue Lifts, or the other Minis can use a short Red Girder to walk past the gray Split Pipe in the floor and head to the coin.