Batman / Superman: World's Finest #12 B9

The secret behind the Supergirl-Robin feud, revealed! On a day not too long ago, a meeting between the Boy Wonder and the Girl of Steel began sweetly, became awkward, and ended so catastrophically, horrifically, jaw-droppingly, car-crashingly disastrously that, among the Superman and Batman families, it is now enshrined as the world's finest example of How Not to Team Up!