When it collides with an individual with sufficient force, the stone creates a wormhole that propels both the stone and the individual through a series of alternate dimensions, splitting the individual into a number of forms before they land back in the main universe. The majority of forms created by the stone's effects are simple clones and recolors of their "pure" progenitors, but stranger results have been reported as well.
Stone Luigi built the stone several years before the Form Wars, first using it on Brooklyn Mario. Further experimentation resulted in thousands of new Mario forms scattered around places like Gamelon and Toad Town. He later used it to expand the forces of the Mama Luigi Army until Gnorris stole it during the Great Eluryhian Offensive. It was placed in the custody of the Hylian military after the war's end, giving Evil Link access to its powers...