Eternium



Eternium is the most powerful substance on the planet Eternia. Just a little piece can act as a source of energy for the city of Eternos for a long time. It's almost impossible to find. If Trap Jaw eats Eternium, he becomes as strong as He-Man, if not stronger, but the substance is poisonous for other beings. There also exists a similar-looking substance named Deterium, but it's useless for anything.

He-Man and the Masters of the Universe (classic cartoon)

 * Double Edged Sword

Golden Books Hardcover

 * The River of Ruin

He-Man and the Masters of the Universe (2002)

 * Trust

Masters of the Universe: Revelation

 * The Forge at the Forest of Forever (mentioned)