DC

In Ancient Egypt, during the reign of Ramses II, an alchemist discovered a fallen meteor and took a shattered fragment which he used as the headpiece to a scepter. He presented the scepter as well as the rest of the meteorite to the pharaoh Ahk-Ton. The scepter was named the Orb of Ra. Exposure to the radiation from the meteor had a transmutative effect on Akh-Ton's body and he became the first Metamorpho.

Major Story Arcs

Outsiders: Five of a Kind

For more information see: Outsiders: Five of a Kind - Metamorpho/Aquaman

Somehow Simon Stagg, gets a hold of the Orb of Ra and takes it to Middle East where he uses it to attempt to purify the water supply he has discovered. Simon tries to use the Orb to keep the locals away but somehow an Arabian woman is able to steal the Orb and use it against Stagg and his army.

When Metamorpho and Arthur Curry, the Aquaman at the time, go to the Middle East to look into the missing army the woman attacks them. She is being controlled by the Orb and it is only with teamwork that Metamorpho and Aquaman are able to stop her.

Realizing that the woman was under the Orb's control when she killed the soldiers, he makes a deal with her. He would get rid of Stagg if she helped him destroy the Orb. She agrees and after getting rid of Stagg, Metamorpho destroys the Orb of Ra.

New 52

Recently, David Graves stole it from ARGUS for as of yet unknown reasons.

Marvel

Said to have been created by Ammon Ra, it has the power to raise and secure the dead.