WARNING: The following contains spoilers for Action Comics #1025 by Brian Michael Bendis, John Romita Jr, Klaus Janson, Brad Anderson, and Dave Sharpe, on sale now Befitting a hero of such immense strength, it makes sense that Superman would have some pretty impressively powerful foes in his rogue's gallery. Some of them even come from across the multiverse to challenge the hero, with the latest potentially even managing to kill off one of his closest allies.
Doctor Glory and the Invisible Mafia just unleashed a seemingly multiversal version of Parasite which quickly attacks the Superman family and even seems to kill Superboy.