Superman #168 (2001)

Superman) returns to Lexor to apprehend Lex Luthor), who has become the revered leader of the planet; while Superman is not only considered a villain, but loses his powers under its red sun.

While disguised as a statue in the Luthor Museum, the Lexorians pile Rainbow Crystals before Superman, as a tribute to Lex Luthor. The crystals greatly concern Superman and he stuffs them all in a bag and escapes the museum, but not for long. Luthor has been feverishly restoring old technology that gives him temporary superpowers, which he uses as "The Defender") to find, capture and imprison Superman. Luthor notes the irony as he looks at Superman behind bars.

The Robotic Guard was a poor choice, as Superman exploits its dogmatic nature to escape and reprograms it to steal the Rainbow Crystals and bring them to his spacecraft. Luthor -- as "The Defender" -- follows the robot and recaptures Superman. But as the mind-numbing properties of the Rainbow Crystals are explained to Lex, he realizes that their emissions are what had destroyed the Lexorian's understanding of any kind of technology.

A truce is reached and Superman is allowed to leave, with a promise to destroy the crystals and protect Lex's secret identity as the Defender.