Flip
Dimension Flipping is a major part of the game Super Paper Mario. At the push of the 'A' button, Mario goes from 2D to 3D. However, there is a time limit as to how long he can stay in 3D, this is called the Flip Meter (which will never decrease after Mario collects his own Catch Card). The ability was given to him by Bestovius in return for all the money in Mario's possession, or for free, depending on whether or not the player refuses Bestovius's second offer.
Mario is not the only character in the game with the ability to flip dimensions, however; throughout the game, there are many enemies with a dotted line around them that can also flip. When Mario goes into 3D, they will flip to follow him and continue to attack him there. Also, some enemies, like the Cursya, are three-dimensional to begin with, so they will also continue to pose a threat.
While most of the time going 3D will solve problems, there are also some times where it actually complicates movement. For example, in 2D there may be a straight line of ? blocks. In 3D, the blocks could end up being totally separated on opposite sides of the levels.
Dimension Flipping is (in a way) also found in Super Mario Galaxy. In Super Mario Galaxy, there are a few sections where Mario would have to travel in a 2D perspective. When Mario set foot into these areas, a dimensional flip would be triggered, seamlessly switching from 3D perspective to 2D. Most of these areas are reached via Warp Pipe and take place underground, and all feature gravity-changing puzzle solving..
