This issue has variants.
New Teen Titans cameo, also 536; vs Hive, also in 533; story continues in Action Comics #533. Per John McDonagh via the GCD Error list (December 22, 2006), "Robin tells Superman that Willis Darrow from New Teen Titans#16 was one of his old foes. However, any previous appearances of Willis Darrow remain unlocated."
This story is titled "Carnaval of Catastrophe!," which is not a typo for "Carnival of Catastrophe!" Credits for script, pencils and inks confirmed from Julius Schwartz's editorial records, provided by DC Comics.