For comic book fans, Muhammad Ali was more than just a great boxer. He was also the star of the famous Superman Vs Muhammad Ali one-shot back in 1978, which is arguably one of the most iconic appearences by a real-life celebrity in the history of comics.
Of course, real people appearing in comic books is hardly a new or rare thing. Stan Lee and Jack Kirby famously wrote (and drew) themselves getting turned away from the wedding of Reed Richards and Sue Storm in 1965’s Fantastic Four Annual #3, while Grant Morrison took the word “comic creator” one step further by writing himself into the 1990 finale of his Animal Man run as the almighty “creator” of the character’s comic-book world.