This is the series finale.
Three characters of Looney Tunes appear in this episode as a parody on Superman's enemies: Marvin the Martian - as Brainiac; Elmer Fudd - as Lex Luthor; Daffy Duck - as General Zod.
This series finale was originally aired in the US on December 3, 2013 before it premiered any other countries until it reran in the United States on August 31, 2014.