Spawnage is the ability to spawn anything from absolutely nothing. It uses the elemental energy Randora, the energy of Quantum Mechanics.
There are two types of Spawnage: Specific Spawnage and Universal Spawnage.
Specific Spawnage is the ability to spawn a specific item or items. Hammer Bros. spawning Hammers and someone who ate a Fire Flower are examples of Specific Spawning.
Universal Spawnage is the ability to spawn absolutely anything at will. There are no limitations to what one can spawn if they can use this type of spawnage. An example of this would be the Random Guy, a Shy Guy that came in contact with Randora.