Dimension D is the name of a small, but surreal and magical, infintely green alternate dimension (with an exception of the said dimension's small but visible yellowish hue on its ceilings, walls, and floors) created by the magic powers of the evil clown Dimentio and a location in the 2007 videogame Super Paper Mario.
Originally this place was intended to multiply the power of Dimentio by 256, the feat was unintentionally granted to all who entered, meaning that relatively speaking everyone's stats remained the same (although Dimentio himself did implied after their first encounter that he may have actually hoped for that to happen in regards to the hero Mario and his allies). Dimentio first challenges the heroes at Dimension D in the Dotwood Tree of The Bitlands.
The player also fights a powerful, brainwashed O'Chunks twice here.
In the second fight he has been brainwashed by a Floro Sprout and is called O'Cabbage in Dimension D during the last stage of Floro Caverns.
When his former master Count Bleck was defeated, Dimentio sends him, an unconscious Nastasia, and Tippi to this realm but all of them escape later due to the power of the Pure Hearts that aided them, despite the fact that Dimension D was made to be "inescapable".
- The fact that Dimentio's power is multiplied 256 fold could be a reference to the Wii's 256 bit computing power, the 256-color scheme used in all the Paper Mario games, or even the fact that the number of catch cards available is 256.
- Despite Dimentio's power multiplied by 256, anyone else in the dimension also gets a strength increase.
- Dimension may be a homage to 8-bit storage capacity; objects are stored in a maximum of 256 values (0 to 255) and going past the max value would revert back to one.