Incarceration would prove no obstacle for the mirthful meance. Despite Arkham’s efforts to contain him, he viewed it as sort of a revolving door. His crimes vary from the whimsically indifferent to the inhumanly brutal. Joker stole Mxyzptlk’s reality-altering power, remaking the world into a twisted caricature with everyone in it stuck in a loop. Joker entertained himself with murder, such as killing Lex Luthor and devouring China’s entire population. Superman’s powerful will allowed him to fight off Joker’s influence enough to make contact with the weakened Mxyzptlk, who, along with Spectre, encouraged Superman to work out Joker’s weakness before reality was destroyed. As time ran out, Superman realized Joker still could not erase Batman from existence, as Joker totally defines himself by his opposition to the Dark Knight; by this logic, Joker would be incapable of destroying the universe. This broke his control, so Mxyzptlk and the Spectre reconstructed reality from the moment Joker disrupted everything. However, Batman was left broken from experiencing multiple deaths, so Superman had to erase Batman’s memories in order for the Dark Knight to go on.
I Love My Halloween Batsuit, by Jimmy Kerast.