Doctor Natas

Dr. Natas was a former member of the Legion of Doom that once nearly destroyed the Justice League of America with his invention, the Noxium crystal. His plans failed however, when he was defeated, and Superman seized the crystal and sealed it in a box made of Krypton steel, and buried it far below the Hall of Justice.

Reference

 * COTSF: "SuperFriends: Rest In Peace"