The Crystal Cage was a magical medallion created by D'Shane.
D'Shane created the Crystal Cage to entrap Solego. D'Shane challenged Solego to a fight, and then used a polished shield to reflect Solego's magic back at him, splitting Solego in two. Solego's mind was trapped in the medallion's crystal, and his powers were trapped in the gold casing. D'Shane then stuck the two halves in a block of jade to prevent them from touching, for if they are ever joined together, it will free Solego.
Professor Potsherd discovered the Crystal Cage on an archaeological expedition to Rakkinroon. Unfortunately, he lost it shortly thereafter in a raid by Sky Pirates. The gold setting was found by Scrooge McDuck while diving off the coast of Wauie-Zauie. The crystal was found by Rebecca Cunningham. Upon touching it, she was possessed by Solego and forced to try to help him find the gold setting. She was ultimately freed, and the crystal was cast into the sea.
The crystal passed through many hands through the years, until Solego possessed Peg-Leg Pete's new car one day. After Solego totalled the car, he called the towing company, allegedly in Scrooge's name, and told them to tow the car to the Money Bin. After trying to explain to the towing company that Scrooge did not want the car, Fenton Crackshell glanced under the car's hood and encountered the crystal. Before it was able to possess him entirely, Fenton summoned the Gizmosuit. Solego then lost interest in Fenton, and possessed the Gizmosuit instead. Solego first broke into the Money Bin to look for the gold setting, then when he discovered it wasn't there, he went to the jewellers in St. Canard where Scrooge was having it polished. Solego got it and freed himself. Darkwing Duck ultimately managed to reimprison Solego by using a satellite dish, the same way that D'Shane used his polished shield. The two halves of the medallion were then returned to the block of jade, which was buried deep within Scrooge's Money Bin.
Behind the scenes
The Crystal Cage is the main macguffin in the 1994 story The Legend of the Chaos God.