Lex Luthor is having a memory problem. There are roughly 85 years and counting worth of Lex Luthor memories in the comics library, from his greatest victories to his worst defeats.
However, some memories may be better off staying lost. However, his parents took things a bit further by pretending Lex was dead. Why are you just telling me this now? Even for a Luthor. Using a time machine, Lex travels to the past, taking a piece of Red Kryptonite as insurance. Luthor then spends hours taunting the frozen Superboy, until he sees a wounded Abraham Lincoln being rushed to the Peterson House.
Luthor then realizes that Superboy had traveled back in time to stop the Lincoln assassination and he had accidentally prevented him.
Realizing what he had done, Luthor is overwhelmed with guilt. Unfortunately for Lex, the Joker disrupts the process, and through the magic of comic book science, the machine causes Luthor and the Joker to switch personalities. He shatters his favorite diamonds, robs banks and gives the money to the poor, and galivants around the city acting like Daffy Duck. Luthor discovered that he was dying due to prolonged exposure to Kryptonite. This clone was genetically engineered to have long flowing red hair and Lex pretended it was his son, Lex Luthor II.
This entire plot may feel like a silly Silver Age tale, but nope. Lex then pretends to reform via some complicated brainwashing and romances the Angela clone. This culminates in a wedding, where Luthor encouraged his best man Superman to give the bride a friendly kiss.
