Superman vs Muhammad Ali comic book from DC Comics
Possibly the strangest team-up of all time.  It also was one of the coolest covers as the back cover was full of celebrities.  Sorta like comic's version of the Sgt. Pepper album.  They even have a list of all the celebrities inside the book.

       

This is a scan of an old comic book. This item is not for sale. But you can find it on ebay.
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