Skeleton is the 8th Expert floor in Monkey Ball and Super Monkey Ball, and the 7th Expert stage in Super Monkey Ball Deluxe. It also appears as the 117th Ultimate stage with continues, and the 157th without.
Skeleton starts off much like Slopes, with each slope you go down getting progressively smaller and steeper. However, the platforms between each slope now feature large rectangular holes with outlining sides that get thinner and thinner with each platform you cross.
Just like Slopes, simply head down each slope until you get to the goal. Since the lines start off much smaller, take it easily, especially whenever it comes to the sections in between platforms and the last few slopes. However, since you only have 30 seconds to beat this stage, speed will also have to be taken into great consideration, too. Also, take care whenever you're going down that last slope, too. Too much speed will result in you flying straight off the stage.
Right when the stage starts, turn your ball to the side and pull back, then charge off and time your landing correctly on the adjacent platform. Repeat this process again of leaping to the adjacent lower platform. However, it will be more difficult due to them being more far apart, so add some more speed to your charge while still being careful with your landing, and you will have just pretty much skipped most of the stage. All that will be left to do is to go down that last slope that leads to the goal.