Lex Luthor Took Forty Cakes is a popular comic book illustration from the 1978 children's dictionary The Super Dictionary featuring illustrations of heroes and villains from DC comics. One of the illustrations in the book depicts Lex Luthor, the super-villain character and arch enemy of Superman, running away with a cart filled with 40 cakes.
The Super Dictionary was published by Holt, Rinehart & Winston in July 1978. The book features more than 4,000 alphabetically arranged words, each defined within story sentences involving various DC comic book characters like Wonder Woman, Aquaman and Flash among others. While the illustrations were meant to educate children through popular DC superheroes, some of the more absurd and campy situations portrayed in the book became a subject of internet mockeries. One of the most memorable instances involves the supervillain character Lex Luthor stealing a cart full of cakes (shown bellow, right).
When no one was looking, Lex Luthor
took forty cakes. He took 40 cakes.
That's as many as four tens.
And that's terrible.
After the slang term "kek" became popular, an Expand Dong version of the image became popular that replaced the word "cake" with the homophone "kek". The usage became synonymous with "lulz" on image boards.
The popularity of Forty Cakes has led it to be introduced into the DC Comics canon. Superman #709 released on March 16, 2011, features a flashback where Clark Kent has been placed in detention during his high school years for skipping class. During his detention he has one of his first encounters with a young Lex Luthor:
 Ebaumsworld Forums via Wayback Machine – When no one was looking, Lex Luthor took forty cakes.
 Comic Book Resource Forums – Lex Luthor stealing forty cakes vs. the Joker stealing a kid's report card