Joey Mason is the young son of Rex Mason and Sapphire Stagg. A mutant, he inherited his father's ability to affect chemical properties. Whereas Rex (aka Metamorpho) can alter the physical properties of his own body, Joey could transmutate the chemical bonds of other objects. Sapphire gave birth to Joey during a time when she was estranged from her husband, and Rex didn't learn of his son's existence for several years. 
His grandfather, Simon Stagg saw Joey as a veritable King Midas who could literally transform lead into gold. He took a personal interest in Joey's well-being and constructed a special nursery for him in his laboratory at Stagg Mansion. When Metamorpho learned that Joey was being kept at Stagg's place, he broke into the laboratory and rescued him. 
Metamorpho had come to discover that the Orb of Ra, the same mystical artifact responsible for giving him his elemental powers, might also hold the key to curing Joey. Along with fellow metamorphae Jillian Conway, Metamorpho brought him all across the globe in search for the Orb, stopping first in Ireland, then Casablanca, and finally back to Egypt. Joey was exposed to radiation from the original meteor responsible for giving Metamorpho his powers and was instantly cured of his condition. 
- Molecular Reconstruction: Joey Mason can alter the chemical bonds of any material, transforming them from one element into another.
- Joseph Mason is not to be confused with colourist Joey Mason.
- 10 Appearances of Joseph Mason (New Earth)
- 2 Images featuring Joseph Mason (New Earth)
- Quotations by or about Joseph Mason (New Earth)
- Character Gallery: Joseph Mason (New Earth)
|Characters||Metamorpho | Sapphire Stagg | Simon Stagg | Java | Element Girl | Joey Mason|
|Teams||Justice League America | Justice League Europe | Outsiders | Doom Patrol|
|Villains||Doc Dread | The Thunderer | Maxwell Tremaine | Ahk-Ton | The Phantom of Washington | Jillian Conway|
|Miscellanea||Metamorphae | Elemental Transmutation | Orb of Ra | Stagg Mansion | Stagg Enterprises|
|Creators||Bob Haney | Ramona Fradon | Sal Trapani | Mark Waid | Graham Nolan | Dan Jurgens|
|Comics||Metamorpho (Volume 1) | Metamorpho (Volume 2) | Metamorpho: Year One | Batman and the Outsiders (Volume 1) | Batman and the Outsiders (Volume 2) | Outsiders (Volume 1) | Outsiders (Volume 3) | Justice League Europe|