Plasma Ore

Plasma Ore is the mysterious substance found in every single transformation item.

History
When the Plasma Sun went on line and showered the planet now known as the Land of Light with its biology altering rays, Plasma Ore came into existence. This substance would later be used by the Ultras to create the transformation items that allow them to change back into their Ultra forms.

Nature
While their nature is unknown the incident with Jack's Bracelet, heavily implies that the substance is merely used to hold the 'light' of an Ultra while the assume human form. This was shown when said light returned to the powerless Jack, allowing him to transform while the Plasma Ore from his bracelet remained inside a monster.

Trivia

 * It is unknown what Plasma Ore's standing in the current series is.
 * Plasma Ore may possibly the inspiration of Plasma Soul, which appears in the Ultra Frontier series/games.